52671 + Interview Questions in Chemistry in Class 11

1.	Assertion. The heat absorbed during isothermal expansion of an ideal gas against vacuum is zero. Reason. The volume occupiedby the molecules is zero.
Answer» If both A and R are true,ANDR is the TRUEEXPLANATION of A. If both A and R are true,but R is not the true explanation of A. If A is true, but R is false If both A and R are false. Answer :c

Discussion

2.	Assertion : The gases show ideal behaviour when the volume occupied is large so that the volume of the molecules can be neglected in comparison to it .Reason : The behaviour of the gas becomes more ideal when pressure is very low .
Answer» If both ASSERTION and reason are TRUE and reason is the correct explanation of assertion . If both assertion and reason are true but reason is NOTTHE correct explanation of assertion . If assertion is true but reason is false . If both assertion and reason are false . Solution :For 1 mole of real gas, `(P+(a)/(V^(2)))(V-b)=RT` when V is very large, the terms b and `a//V^(2)` are negligible and the van der Waals equation becomes ideal gas equation, PV = RT hence, real gases behave like ideal gas.

Discussion

3.	Assertion : The fourth series (4n+1) starts with plutonium -241 and ends with bismuth -209 is known as Neptunium series. Reason : Neptunium is a naturally occuring element
Answer» Both A and R are true and R is the correct EXPLANATION of A Both A and R are true but R is not a correct explanation of A A is true but R is FALSE A is false but R is true Answer :C

Discussion

4.	Assertion : The fluorides of alkaline earth metals are almost insoluble in water. Reason: The lattice energies of the fluorides of alkaline earth metal are very high.
Answer» both ASSERTION and reason are true and reason is the CORRECT explanation of assertion both assertion and reason are true but reason is not the correct explanation of assertion assertion is true but reason is false both assertion and reason are false Answer :A

Discussion

5.	Assertion. The free gaseous Cr atom has six unpaired electrons Reason. Half-filled s-orbital has grater stability.
Answer» If both ASSERTION and reason are true, and reason is the true EXPLANATION of the arrertion If both assertion and reason are true, but reason is not the true explanation of the assertional If assertion is true, but reason is false If both assertion and reason are false Solution :Correct R. Half-filled d-orbitals and half-filled s-orbital have greater STABILITY.

Discussion

6.	Assertion: (A) Boron has a smaller first ionsation enthalpy than beryllium. Reason( R) The penetration of 2s electron to the nucleus is more than the 2p electron hence 2p elecrons is more shielded by the inner core of electrons than the 2s electrons.
Answer» If both Assertion and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion. If Assertion is CORRECT but Reason is INCORRECT. If Assertion is INCORRECT but Reason is CORRECT. Answer :C

Discussion

7.	Assertion: The first ionisation energy of Be is greater than boron. Reason: 2p-orbitals have lower energy than 2s-orbital
Answer» Both A and B TRUE and R is the CORRECT explanation A Both A and R are true but R is not a correct explanation of A A is true but R is FALSE A is false but R is true Answer :C

Discussion

8.	Assertion : The experimentally determined carbon to oxygen bond length in carbon dioxide is 115 pm. Reason :The lengths of a normal carbon to oxygen double bond(C=O) and carbon to oxygen triple bond (C-=) are 121 pm and 110 pm respectively.
Answer» If both ASSERTION and reason are TRUE and reason is the correct explanation of assertion. If both assertion and reason are true but reason in not the correct explanation of assertion. If assertion is true but reason is false. If both assertion and reason are false. Solution :In carbon dioxide, the carbon - oxygen bond LENGTHS lie in between the values for (C = O) and `(C-= O)` bond lengths because carbon dioxide is a resonace hybrid of following STRUCTURES : `underset(I)( :overset(..)(O) ::C::overset(..)(C): ) harr underset(II)( :underset(..)overset(..^(-))(O: )C vdots vdotsoverset(+)(O): ) harr underset(III)( :overset(+)(O)vdots vdots C :underset(..)overset(..^(-))(O: ))`

Discussion

9.	Assertion. The enthalpy of formation of gaseous oxygen molecules at 298 K and under a pressure of one atmosphere is zero. Reason. The entropy of formation of geseous oxygenmolecule under the same conditions is zero.
Answer» If both A and R are TRUE,ANDR is the TRUEEXPLANATION of A. If both A and R are true,but R is not the true EXPLANATION of A. If A is true, but R is false If both A and R are false. Answer :C

Discussion

10.	Assertion: The enthalpies of neutralisation of strong acids and strong bases are always same. Reason: Neutralisation is heat of formation of water.
Answer» If both ther ASSERTION and reason are true and the reason is the correct explanation of the assertion. If both the assertion and reason are true but reason is not the correct explantion of the assertion. If the assertion is true but reason is FALSE. If assertion is false but reason is true. Solution :The enthalpies of neutralisation of strong acids and strong BASES are the same they are `13.7Kcal` . The reason is that it is heat of FORMATION of water from `H^(+)` and `OH^(-)` ions. `H^(+)+OH^(-)rarrH_(2)O,DeltaH=13.7Kcal` . Thus, both assertion and reason are true.

Discussion

11.	Assertion. The energy of an electron is largely determined by its principal quantum number Reason. The principal quantum number (n) is a measure of the most probable distance of finding the electron around the nucleus.
Answer» If both ASSERTION and reason are TRUE, and reason is the true explanation of the arrertion If both assertion and reason are true, but reason is not the true explanation of the assertional If assertion is true, but reason is false If both assertion and reason are false Answer :A

Discussion

12.	Assertion :The energy of an electron is largely determined by its principal quantum number. Reason :The principal quantum numberis a measure of the most probable distance of finding the electrons around the nucleus.
Answer» If both ASSERTION & REASON are TRUE and the reason is the correct explanation of the assertion. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion. If Assertion is true statement but Reason is FALSE. If both Assertion and Reason are false statements. Answer :A

Discussion

13.	Assertion : The energy of an electron is largely determined by its principal quantum number. Reason : The principal quantum number n is a measure of the most probable distance of finding the electron around the nucleus.
Answer» If both assertion and reason are true and the reason is the correct explanation of the assertion If both assertion and reason are true butreason isnot the correct explanation of the assertion If assertion is true but reason is false If the assertion and reason both are false Solution :We know that principal quantum number REPRESENT the main energy level or energy SHELL. SINCE each energy level is associated with a definite amount of energy, this quantum NUMBERS determines to a large extent energy of an electron. It also determines the average DISTANCE of an electron around the nucleus . Therefore both Assertion and Reason are true and the Reason is a correct explanation of the Assertion.

Discussion

14.	Assertion: The electron affinity of chlorine is greater than that of fluorine. Reason: Chlorine is more electronegative than fluorine.
Answer» Both A and B TRUE and R is the correct explanation A Both A and R are true but R is not a correct explanation of A A is true but R is false A is false but R is true Answer :C

Discussion

15.	Assertion : The drop of a liquid is always spherical or nearly spherical. Reason : Water is not a viscous liquid.
Answer» If both ASSERTION and REASON are CORRECT and Reason is the CORRECT EXPLANATION of the Assertion. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion. If Assertion is CORRECT but Reason is INCORRECT. If Assertion is INCORRECT but Reason is CORRECT. Solution :If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion.

Discussion

16.	Assertion: The dissociation of CaCO_(3) can be represented as, CaCO_(3)(s)hArrCaO(s) + CO_(2)(g) . Some solid CaCO_(3) is placed in an evacuted vessel enclosed by a piston and heated so that the volume of the vessel is doubled, while the temperature is held constant, the number of moles of CO_(2) in the vessel increase. Reason: The pressure ofv CO_(2) in the vessel will remain the same.
Answer» If both assertion and REASON are TRUE and the reason is the CORRECT EXPLANATION of the assertion. If both assertion and reason are true but reason is not the correct explanation of the assertion. If assertion is true but reason is false. If assertion is false but reason is true. Solution :Both assertionand reasion are true and the reason is the correct explanation of the assertion.

Discussion

17.	Assertion : The Daniell cell becomes dead after sometime. Reason : Oxidation potential of zinc anode decreases and that of copper cathode increases.
Answer» ASSERTION and reason both are correct STATEMENTS and reason is correct EXPLANATION for assertion. Assertion and reason both are correct statements but reason is not correct explanation for assertion. Assertion is correct statement but reason is WRONG statement. Assertion is wrong statement but reason is correct statement. Answer :a

Discussion

18.	Assertion The daniel cell becomes dead after some time Reason oxidation potential of zinc anode decrease and that of copper increases
Answer» ANSWER :a

Discussion

19.	Assertion: The conversion of fresh precipitate to colloidal state is called peptization. Reason: It is caused by addition of common ions.
Answer» if both ASSERTION and REASON are true and the reason is the correct explanation of the assertion. If both assertion and reason are true but reason is not the correct explanation of the assertion If assertion is true but reason is false. If the assertion and reason both are false. Solution :Correct reason to assertion is that COMMON ion absorb on the surface of PRECIPITATE. Due to repulsion between adsorbed ions, the precipitate undergo fragmentaion RESULTING in colloidal state.

Discussion

20.	Assertion : The compounds having delocalised electron are more stable than compound having localised electron. Reason : Due to the delocalised electron compound got more stability which is called resonance energy.
Answer» Assertion (A) and Reason (R) both are correct and (R) gives correct EXPLANATION. Assertion (A) and Reason (R) correct, but Reason is not PROPER reason. Assertion is correct, but Reason is wrong. Assertion and Reason both incorrect. Solution :Assertion and Reason correct, but Reason is not proper reason. If electrons are in compound than it indicate resonance. The compound which POSSESS resonance has more stability, but this more stability is explained by molecular ORBITAL theory.

Discussion

21.	Assertion: The carbonate of lithium decomposes easily on heating. Reason: Lithium being very small in size polarises large carbonate ion leading to the formation of more stable Li_(2)O and CO_(2).
Answer» If both ASSERTION and REASON are TRUE and reason is the CORRECT EXPLANATION of assertion If both assertion and reason are true but reason is not the correct explanation of assertion If assertion is true but reason is false. If both assertion and reason are false. Answer :A

Discussion

22.	Assertion. The catalytic converter in the car's exhaust system converts polluting exhaust gases into nontoxic gases Reason Catalytic converter contains a mixture of transition metals and their oxides embedded in the inner support
Answer» If both Assertion and REASON are TRUE and Reason is the CORRECT explanation of Assertion. Both Assertion and Reason are true but Reasonis not the correct explanation of Assertion If Assertion is true but Reason is false If both Assertion and Reason are false Solution :Reason is the correct explanation of Assertion.

Discussion

23.	Assertion : The carbon-carbon bond length in benzene lies between thebond lengths of C-C and C=C bonds found in other molecules.Reason:Benzene exhibits the phenomenon of resonance
Answer» If both ASSERTION and REASON are CORRECT and Reason is the CORRECT EXPLANATION of the Assertion. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion. I Assertion is CORRECT but Reason is INCORRECT. If Assertion is INCORRECT but Reason is CORRECT. Answer :A

Discussion

24.	Assertion . The bond anlge of PBr_(3) is greater than that of PH_(3) but bond angle of NBr_(3) is less than that of NH_(3). Reason .Electronegativity of phosphorus atom is less thanthat of nitrogen .
Answer» If both assertion and reason are correct, and reason is the correct explanation of the assertion. If both assertion and reason are correct , but reason is not the correct explanation of the assertion. If assertion is correct, but reason is incorrect . If both assertion and reason are incorrect. Solution :Correct explanation. The TRUTH of assertion is not due to DIFFERENCE in the electronegativities of N and P but due to difference in electronegativity of H and Br (in `NH_(3) and NBr_(3))` and due to reaonance in ` PBr_(3)` but no resonance in `PH_(3)`

Discussion

25.	Assertion . The atoms in a cavalent molecule are said to share electrons, yet some covalent molecules are polar. Reason . In a polar molecular , the shared elelctrons spend more time than average near one of the atoms .
Answer» If both assertion and reason are CORRECT, and reason is the correct explanation of the assertion. If both assertion and reason are correct , but reason is not the correct explanation of the assertion. If assertion is correct, but reason is incorrect . If both assertion and reason are incorrect. SOLUTION :Correct R . The SHARED pairof electrons remains ATTRACTED towerds the more electronegativate ATOM at all times .

Discussion

26.	The atomic and ionic radii of alkali metals are the smallest in their respective periods.
Answer» If both Assertion and REASON are CORRECT and Reason is the CORRECT EXPLANATION of the Assertion. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion. If Assertion is CORRECT but Reason is INCORRECT. If Assertion is INCORRECT but Reason is CORRECT. Answer :B

Discussion

27.	Assertion : The atomic masses of most of the elements are in fraction. Reason : The atomic mass represents the ratio of the average mass of the atom to one avogram.
Answer» Both assertion and REASON are correct and reason is the correct EXPLANATION for assertion . Both assertion and reason are correct but reason is not the correct explanation for assertion . Assertion is true but reason are FALSE. Both assertion and reason are false ANSWER :A::B::C::D

Discussion

28.	Assertion: The atomic mass of helium is 4.003 amu. Reason: The mass of an atom of helium is 4.003 g.
Answer» If both ASSERTION and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion. If Assertion is CORRECT but Reason is INCORRECT If Assertion is INCORRECT but Reason is CORRECT. Answer :C

Discussion

29.	Assertion : The ash is produced by burning paper in air is lighter than the original mass of paper. Reason : The residue is left after the combustion of a chamical reaction that entities is always lighter.
Answer» Both assertion and REASON are correct and reason is the correct explanation for assertion . Both assertion and reason are correct but reason is not the correct explanation for assertion Assertion is TRUE but reason are FALSE. Both assertion and reason are false Answer :A::B

Discussion

30.	Assertion : The alkaline hydrolysis of ester is reversible Reason : Alkaline hydrolysis yields carboxylate anion which is susceptible to nucleophilic attack
Answer» Both A and R are true is the CORRECT EXPLANATION of A Both A and R are true but R is not a correct explanation of A A is true but R is false Both A and R are false Answer :D

Discussion

31.	Assertion : The alkaline earth metal hydroxides are more basic than the corresponding alkali metal. Reason : The ionisation enthalpies of alkaline earth metals are much lower than those of alkali metals.
Answer» If both ASSERTION and REASON are CORRECT and Reason is the CORRECT explanation of the Assertion. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion. If Assertion is CORRECT but Reason is INCORRECT. Both Assertion and reason are INCORRECT ANSWER :D

Discussion

32.	Assertion : The alkali metal cations have a strong tendency to get hydrated. Reason : The alkali metal cations are quite large in size.
Answer» If both Assertion and REASON are CORRECT and Reason is the CORRECT EXPLANATION of the Assertion. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion. If Assertion is CORRECT but Reason is INCORRECT. If Assertion is INCORRECT but Reason is CORRECT. Answer :B

Discussion

33.	Assertion. The 19th electron in potassium atom enters into 4 s-orbital and not the 3 d-orbital Reason. (n +l) rule is followed for determining the orbital of the lowest energy state.
Answer» If both ASSERTION and reason are true, and reason is the true explanation of the arrertion If both assertion and reason are true, but reason is not the true explanation of the assertional If assertion is true, but reason is false If both assertion and reason are false Answer :A

Discussion

34.	Assertion : Tertiary Carbocations are generally formed more easily than primary Carbocations. Reason : Hyper conjugation as well as inductive effect due to additional alkyl group stabilize tertiary carbonium ions.
Answer» both ASSERTION and REASON are TRUE and reason is the correct explanation of assertion. both assertion and reason are true but reason is not the correct explanation of assertion. Assertion is true but reason is false Both assertion and reason are false Answer :A

Discussion

35.	Assertion : Tertiary Carbocations are generally formed more easily than primary Carbocations ions . Reason : Hyper conjugation as well as inductive effect due to additional alkyl group stabilize tertiary carboninum ions .
Answer» both assertion and REASON are TRUE and reason is the correct EXPLANATION of assertion . both assertion and reason are true but reason is not the correct' explanation of assertion Assertion is true but reason is FALSE Both assertion and reason are false Solution :N/A

Discussion

36.	Assertion : Tertiary carbocations are generally formed more easily than primary carbocations. Reason : Hyperconjugation as well as inductive effect due to additional alkyl groups stabilize tertiary carbocations.
Answer» If both ASSERTION and REASON are CORRECT and reason is correct EXPLANATION for assertion. If both assertion and reason are correct but reason is not correct explanation for assertion. If assertion is correct but reason is incorrect. If both assertion and reason are incorrect. Solution :Reason is the correct explanation for assertion.

Discussion

37.	Assertion : tert-Butyl carbanion is stable than methyl carbanion. Reason : The +I-effect of the three methyl groups in tert-butyl carbanion tends to make it more stable than methyl carbaion.
Answer» If both ASSERTION and Reason are true, and reason is the true EXPLANATION of the assertion. If both assertion and reason are true, but reason is not the true explanation of the assertion. If assertion is true, but reason is false If both assertion and reason are false Solution :Correct assertion. tert-Butyl CARBANION is less stable than methyl carbanion. Correct reason. +I-effect of the `CH_(3)` groups destabilize the tert-butyl carbanion RELATIVE to methyl carbanion.

Discussion

38.	(A) Tertiary carbocations are generally formed more easily than primary carbocations. (R) Hyperconjugation as well as inductiveeffect due to additional alkyl groups stabilize tertiary cabocations.
Answer» If both ASSERTION and REASON are correct and reasonis crect explanation for assertion If both assertion and reason are correct but reasonis not COTTECT explanation for assertion If reason is correct but assertion is incorrect If both assertion and reason are incorrect Answer :a

Discussion

39.	Assertion : Temperature below 0^(@)C is possible on celsius scale but in Kelvin scale negative temperature is not possible Reason :The Kelvin scale is related to celsius scale as K = .^(@)C - 273.
Answer» If both assertion and REASON are true and reason is the correct explanation of assertion If both assertion and reason are true but reason is not correct explanation of assertion. If assertion is true but reason is false. If both assertion and reason are false. Solution :The KELVIN scale is RELATED to Celsius scale as follows : `K=""^@C+273.15`

Discussion

40.	Assertion . Sulphur is estimated as BaSO_(4) and not as MgSO_(4). Reason. The ionic radius of Mg^(2+) is smaller than that of Ba^(2+) .
Answer» If both assertion and REASON are TRUE, and reason is the true explanation of the assertion. If both assertion and reason are true, but reason is not the true explanation of the assertion. If assertion is true, but reason is false If both assertion and reason are false. Solution :Correct explanation . `BaSO_(4)` is insoluble while `MgSO_(4)` is SOLUBLE in water .

Discussion

41.	Assertion Sulphur dioxide and chlorineare both bleaching agents Reason both are reducing agents
Answer» If both assertion and reasn are true and REASON is the true EXPLANATION of the assertion If both assertion and reason are true but reason is not the true explanation of the assertion If assertion is true but reason is false If both assertion and reason are false Solution :Correct reason `CI_(2)` bleaches by oxidation while `SO_(2)` bleaches by REDUCTION

Discussion

42.	Assertion : Starch is used as absorption indicator in iodometric and iodimetric titrations. Reason : Starch forms iodostarch complex with iodine, which is blue coloured.
Answer» If both ASSERTION and REASON are CORRECT, and Reason is the correct EXPLANATION of Assertion. If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. If Assertion is correct, but Reason is INCORRECT. If Assertion is incorrect, but Reason is correct. Solution :N//A

Discussion

43.	Assertion: Staggered conformation of ethane is most stable while eclipsed conformation is least stable. ltbr. Reason: Staggered form has the least torsional strain and the eclipsed form has the maximum torsional strain.
Answer» If both assertion and reson are true and REASON is the CORRECT EXPLANATION of assertion If both assertion and reason are true but reason is not the correct explanation of assertion. If assertion is true but reason is false. If both assertion and reason are false. Answer :A

Discussion

44.	Assertion : Splitting of the spectral lines in the presence of magnetic field is known as stark effect. Reason : Line spectrum is simplest for hydrogen atom.
Answer» If both assertion and reason are true and the reason is the correct EXPLANATION of the assertion If both assertion and reason are true butreason isnot the correct explanation of the assertion If assertion is true but reason is false If assertion is false but reason is true Solution :Assertion is false but reason is true. Splitting of the splitting of the spectral lines in the presence of a MAGNETIC field is KNOWN as Zeeman EFFECT or in electric field it is known as stark effect. The splitting of spectral lines is DUE to different orientations which the orbitals can have in the presence of magnetic field

Discussion

45.	Assertion : Ssemiconductors are solids with conductivities in the intermediate range from10^(-6) - 10^(4) ohm^(-1) m^(-1) Reason : Intermediate conductivity in semiconductor is due to partially filled valence band.
Answer» ASSERTION and reason both are corrct statements and reason is correct explanation for assertion. Assertion and reson both are correct statements but reason is not correct explanation for asseration . Assertion is correct statement but reason is WRONG statement . Assertion is wrong statement but reason is correct statement . SOLUTION :Correct Reason . Intermediate CONDUCTIVITY of semiconductors is due to small energy gap between filled valence band and empty CONDUCTION band.

Discussion

46.	Assertion: Spin quantum number can have the value +1/2 or -1/2. Reason:(+) sign here signifies the wave function.
Answer» If both assertion and reason are true and the reason is the CORRECT EXPLANATION of the assertion If both assertion and reason are true butreason isnot the correct explanation of the assertion If assertion is true but reason is false If the assertion and reason both are false Solution :Assertion is true but reason is false. Spin angular MOMENTUM of the electron, a vector quantity, can have twoorientations (represented by + and - sign) relative to a chosen axis. These two orientation are distinguished by the spin quantum number `m_s` equals to `+1/2` or `-1/2`.These are called the two spin states of the electron and are NORMALLY represented by the two arrows `uarr` (spin up) and `darr` (spin down ) respectively.

Discussion

47.	Assertion: sp^(3) hybrid carbon atom is more electronegative than sp hybrid carbon atom. Reason: sp^(3) hybrid orbitals are more closer to the nucleus.
Answer» If both assertion and reason are true and reason is the correct explanation of assertion If both assertion and reason are true but reason is not the correct explanation of assertion If assertion is true but reason is false. If both assertion and reason are false. Solution :The greater s character of an orbital means it is more CLOSER to the nucleus and it is more electronegative. Hence, sp HYBRID CARBON ATOM is more electronegative.

Discussion

48.	Assertion : Solids possess a rigid structure whereas liquids possess a non-rigid structure. Reason : In solids, the intermolecular distances are much smaller thanthose in liquids.
Answer» If both ASSERTION and REASON are CORRECT and Reason is the CORRECT EXPLANATION of the Assertion. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion. If Assertion is CORRECT but Reason is INCORRECT. If Assertion is INCORRECT but Reason is CORRECT. Solution :If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion.

Discussion

49.	Assertion : Soft water lathers with soap but not hard water. Reason : Hard water reacts with soap to form insoluble salts which form scum, not lather.
Answer» If both ASSERTION and REASON are TRUE and reason is the CORRECT explanation of assertion. If both assertion and reason are true but reason is not the correct explanation of assertion. If assertion is true but reason is false. If both assertion and reason are false. Answer :A

Discussion

50.	Assertion: Sodium salt of butanoic acid on heating with soda lime gives butane. Reason: Decarboxylation reaction yields alkanes having same number of carbon atoms as the parent acid.
Answer» If both assertion and reson are TRUE and reason is the correct explanation of assertion If both assertion and reason are true but reason is not the correct explanation of assertion. If assertion is true but reason is false. If both assertion and reason are false. Solution :Decarboxylation reaction gives alkanes having one carbon atom less than the carboxylic acid. THEREFORE, sodium salt of butanoic acid on heating with SODA LIME gives propane.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Assertion. The heat absorbed during isothermal expansion of an ideal gas against vacuum is zero. Reason. The volume occupiedby the molecules is zero.

Assertion : The gases show ideal behaviour when the volume occupied is large so that the volume of the molecules can be neglected in comparison to it .Reason : The behaviour of the gas becomes more ideal when pressure is very low .

Assertion : The fourth series (4n+1) starts with plutonium -241 and ends with bismuth -209 is known as Neptunium series. Reason : Neptunium is a naturally occuring element

Assertion : The fluorides of alkaline earth metals are almost insoluble in water. Reason: The lattice energies of the fluorides of alkaline earth metal are very high.

Assertion. The free gaseous Cr atom has six unpaired electrons Reason. Half-filled s-orbital has grater stability.

Assertion: (A) Boron has a smaller first ionsation enthalpy than beryllium. Reason( R) The penetration of 2s electron to the nucleus is more than the 2p electron hence 2p elecrons is more shielded by the inner core of electrons than the 2s electrons.

Assertion: The first ionisation energy of Be is greater than boron. Reason: 2p-orbitals have lower energy than 2s-orbital

Assertion : The experimentally determined carbon to oxygen bond length in carbon dioxide is 115 pm. Reason :The lengths of a normal carbon to oxygen double bond(C=O) and carbon to oxygen triple bond (C-=) are 121 pm and 110 pm respectively.

Assertion. The enthalpy of formation of gaseous oxygen molecules at 298 K and under a pressure of one atmosphere is zero. Reason. The entropy of formation of geseous oxygenmolecule under the same conditions is zero.

Assertion: The enthalpies of neutralisation of strong acids and strong bases are always same. Reason: Neutralisation is heat of formation of water.

Assertion. The energy of an electron is largely determined by its principal quantum number Reason. The principal quantum number (n) is a measure of the most probable distance of finding the electron around the nucleus.

Assertion :The energy of an electron is largely determined by its principal quantum number. Reason :The principal quantum numberis a measure of the most probable distance of finding the electrons around the nucleus.

Assertion : The energy of an electron is largely determined by its principal quantum number. Reason : The principal quantum number n is a measure of the most probable distance of finding the electron around the nucleus.

Assertion: The electron affinity of chlorine is greater than that of fluorine. Reason: Chlorine is more electronegative than fluorine.

Assertion : The drop of a liquid is always spherical or nearly spherical. Reason : Water is not a viscous liquid.

Assertion : The Daniell cell becomes dead after sometime. Reason : Oxidation potential of zinc anode decreases and that of copper cathode increases.

Assertion The daniel cell becomes dead after some time Reason oxidation potential of zinc anode decrease and that of copper increases

Assertion: The conversion of fresh precipitate to colloidal state is called peptization. Reason: It is caused by addition of common ions.

Assertion : The compounds having delocalised electron are more stable than compound having localised electron. Reason : Due to the delocalised electron compound got more stability which is called resonance energy.

Assertion: The carbonate of lithium decomposes easily on heating. Reason: Lithium being very small in size polarises large carbonate ion leading to the formation of more stable Li_(2)O and CO_(2).

Assertion. The catalytic converter in the car's exhaust system converts polluting exhaust gases into nontoxic gases Reason Catalytic converter contains a mixture of transition metals and their oxides embedded in the inner support

Assertion : The carbon-carbon bond length in benzene lies between thebond lengths of C-C and C=C bonds found in other molecules.Reason:Benzene exhibits the phenomenon of resonance

Assertion . The bond anlge of PBr_(3) is greater than that of PH_(3) but bond angle of NBr_(3) is less than that of NH_(3). Reason .Electronegativity of phosphorus atom is less thanthat of nitrogen .

Assertion . The atoms in a cavalent molecule are said to share electrons, yet some covalent molecules are polar. Reason . In a polar molecular , the shared elelctrons spend more time than average near one of the atoms .

The atomic and ionic radii of alkali metals are the smallest in their respective periods.

Assertion : The atomic masses of most of the elements are in fraction. Reason : The atomic mass represents the ratio of the average mass of the atom to one avogram.

Assertion: The atomic mass of helium is 4.003 amu. Reason: The mass of an atom of helium is 4.003 g.

Assertion : The ash is produced by burning paper in air is lighter than the original mass of paper. Reason : The residue is left after the combustion of a chamical reaction that entities is always lighter.

Assertion : The alkaline hydrolysis of ester is reversible Reason : Alkaline hydrolysis yields carboxylate anion which is susceptible to nucleophilic attack

Assertion : The alkaline earth metal hydroxides are more basic than the corresponding alkali metal. Reason : The ionisation enthalpies of alkaline earth metals are much lower than those of alkali metals.

Assertion : The alkali metal cations have a strong tendency to get hydrated. Reason : The alkali metal cations are quite large in size.

Assertion. The 19th electron in potassium atom enters into 4 s-orbital and not the 3 d-orbital Reason. (n +l) rule is followed for determining the orbital of the lowest energy state.

Assertion : Tertiary Carbocations are generally formed more easily than primary Carbocations. Reason : Hyper conjugation as well as inductive effect due to additional alkyl group stabilize tertiary carbonium ions.

Assertion : Tertiary Carbocations are generally formed more easily than primary Carbocations ions . Reason : Hyper conjugation as well as inductive effect due to additional alkyl group stabilize tertiary carboninum ions .

Assertion : Tertiary carbocations are generally formed more easily than primary carbocations. Reason : Hyperconjugation as well as inductive effect due to additional alkyl groups stabilize tertiary carbocations.

Assertion : tert-Butyl carbanion is stable than methyl carbanion. Reason : The +I-effect of the three methyl groups in tert-butyl carbanion tends to make it more stable than methyl carbaion.

(A) Tertiary carbocations are generally formed more easily than primary carbocations. (R) Hyperconjugation as well as inductiveeffect due to additional alkyl groups stabilize tertiary cabocations.

Assertion : Temperature below 0^(@)C is possible on celsius scale but in Kelvin scale negative temperature is not possible Reason :The Kelvin scale is related to celsius scale as K = .^(@)C - 273.

Assertion . Sulphur is estimated as BaSO_(4) and not as MgSO_(4). Reason. The ionic radius of Mg^(2+) is smaller than that of Ba^(2+) .

Assertion Sulphur dioxide and chlorineare both bleaching agents Reason both are reducing agents

Assertion : Starch is used as absorption indicator in iodometric and iodimetric titrations. Reason : Starch forms iodostarch complex with iodine, which is blue coloured.

Assertion: Staggered conformation of ethane is most stable while eclipsed conformation is least stable. ltbr. Reason: Staggered form has the least torsional strain and the eclipsed form has the maximum torsional strain.

Assertion : Splitting of the spectral lines in the presence of magnetic field is known as stark effect. Reason : Line spectrum is simplest for hydrogen atom.

Assertion : Ssemiconductors are solids with conductivities in the intermediate range from10^(-6) - 10^(4) ohm^(-1) m^(-1) Reason : Intermediate conductivity in semiconductor is due to partially filled valence band.

Assertion: Spin quantum number can have the value +1/2 or -1/2. Reason:(+) sign here signifies the wave function.

Assertion: sp^(3) hybrid carbon atom is more electronegative than sp hybrid carbon atom. Reason: sp^(3) hybrid orbitals are more closer to the nucleus.

Assertion : Solids possess a rigid structure whereas liquids possess a non-rigid structure. Reason : In solids, the intermolecular distances are much smaller thanthose in liquids.

Assertion : Soft water lathers with soap but not hard water. Reason : Hard water reacts with soap to form insoluble salts which form scum, not lather.

Assertion: Sodium salt of butanoic acid on heating with soda lime gives butane. Reason: Decarboxylation reaction yields alkanes having same number of carbon atoms as the parent acid.