52671 + Interview Questions in Chemistry in Class 11

1.	Assertion : The total number of atoms present in a simple cubic unit cell is one. Reason : Simple cubic unit cell has atoms at its corners , each of which is shared between eight adjacent unit cells.
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

2.	Assertion. The temperature in the stratosphere increases with altitude Reason. Ozone present absorbs the ultraviolet radiation.
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 Answer :A

Discussion

3.	Assertion. The temperature of a gas does notchange when it undergoes an adiabatic expansion. Reason . During an adiabatic expansion of a real gas, the internal energy of the gas remains constant.
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 :d

Discussion

4.	Assertion. The sum of the radii of Na^+ and Cl^- ions in NaCl crystal is 281 pm. Hence, edge of the unit cell is 281 pm Reason. Edge of the unit cell is the distance between the centres of Na^+ and Cl^- ions touching each other .
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 A . The edge of NACL UNIT CELL is the distance from `Na^+` to NEXT `Na^+` ion or from `Cl^-` ion to next `Cl^-` ion. Correct R. Edge of the unit cell of NaCl is DOUBLE the distance between the centre of `Na^+` and `Cl^-` ions touching each other.

Discussion

5.	Assertion : The strength of haloacids increases in the order : HIltltBHrltltHClltltHF Reason : Strength of acid HA depends only on the electronegatively difference between H and A.
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 correct order of acidic strength is `HFltltHClltltHBrltltHI`. While comparing ELEMENTS in the same group of the periodic table, H-A bond strength is a more important factor in determining acidity than its polar NATURE. As the size of A increases down the group, H-A bond strength decreases and so the ACID strength increases.

Discussion

6.	Assertion : The standard unit of expressing mass of atoms is called 'u' Reason :'u' represents unit mass.
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 :u' represent UNIFIED mass.

Discussion

7.	Assertion : the spectrum of He^(+) is expected to be similar to that of hydrogen Reason : He^(+) is also one electron system
Answer» If both assertion and reason are trueand reason is the correct EXPLANATION of assertion. If both assertion and reason are true but reason is no the correct EXPLANTION of assertion. If assertion is true but reason are FLASE If both assertion and reason are false ANSWER :A

Discussion

8.	Assertion : The spectrum of He^(+) is expected to be similar to that of hydrogen Reason : He^(+) is also one electron system.
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 :If both assertion and resaon are true and reason is the correct explanation of assertion.

Discussion

9.	Assertion The spectrum of He is expected to be similar to that of hydrogen Reason: He^(+) is also one electron system
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 f assertion is true but reason is false If both assertion and reason are false Solution :If both assertion and reason are true and reason is the correct explanation of assertion

Discussion

10.	Why are the solutions of alkali metal atoms in liquid ammonia blue coloured and highly conducting?
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 :A

Discussion

11.	Assertion : The solubility of most salts in water increases with rise of temperature. Reason : For most of the ionic compounds, Delta_("sol")H^(@) is positive and the dissociation process is endothermic.
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

12.	Assertion: The SI unit of force is kg m^(2) s^(-2) Reason: Force = mass x acceleration. The SI unit of mass is kg and that of acceleration is ms^(-2).
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 :D

Discussion

13.	Assertion: The second substituent may enter the mono-substituted benzene ring at either ortho, para or at meta position. Reason: The position of the incoming group is determined by the natrue fo the group present in monosubstituted benzene ring.
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 :The nature of the substituent decides the position of incoming group. GROUPS are EITHER o,p-directing or m-directing.

Discussion

14.	Assertion : The S-S-S bond angle in S_8 molecule is 105^@ Reason:S_8 has a V-shape.
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 :As atoms in `S_8` molecule UNDERGO `sp^3` hybridisation and contain two LONE pairs of electrons on each and exists as staggered 8 atoms-rings.

Discussion

15.	Assertion . The resonance hybrid is more stable than any of the contributing structure . Reason . The contributing structures contain the same number of umpaired elelctrons and have the real existance.
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 :CorrectR . The contributing structures contain the same number of upraired ELECRONS but do not have REAL EXISTENCE .

Discussion

16.	Assertion : The relative proportion of atoms of THtium and Protium is 1 : 10^(17) Reason : The property responsible for the low proportion of Tritium is its non-radioactivity.
Answer» Assertion is false but REASON is TRUE Assertion is true but reason is false Both assertion and reason are true Both assertion and reason are true and reason is the correct explanation of the assertion. Answer :B

Discussion

17.	Assertion: The relative proportion of Tritium and Protium is 1: 10^17 Reason: The property responsible for the low proportion of Tritium is its non-radioactivity.
Answer» Both assertion and REASON are TRUE. Both assertion and reason are true and reason is the CORRECT explanation of the assertion. Assertion is false but reason is true. Assertion is true but reason is false. Answer :D

Discussion

18.	Assertion: The reaction, C_(2)H_(5)Br +2Na+C_(2)H_(5)Br to C_(4)H_(10)+2NaBr is known as Wurtz reaction. Reason: The reaction is carried out in presence of dry ether.
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 :B

Discussion

19.	Gases deviate from the ideal gas behaviour because their molecules
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 Assertion is CORRECT but Reason is INCORRECT.

Discussion

20.	Assertion : The reaction 2NO (g) + O_(2) (g) hArr 2NO_(2)(g) is favoured in the forward direction with increase ofpressure. Reason : The reaction is exothermic.
Answer» if both assertion and reason are correct and reason is CORRECTEXPLANATION 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 assertion and reason boht are incorrect. Solution :Correct explanation. FORWARD reaction is ACCOMPANIED by decreasein pressure.

Discussion

21.	Assertion:The reactant which is present in large amount limits the amount of product formed is called limiting reagent. Reason : Amount of product formed does not depend upon the amount of reactants taken.
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 reactant which is present in lesser amount gets consumed after sometime and after that no further reaction taked place WHATEVER be the amount of the other reactant present. HENCE, the reactant which gets THEREFORE, called the limiting reagent.

Discussion

22.	Assertion : The reacting gases combine in volumes that are ratios of small whole number Reason : The partial pressure of a gas in a mixture is given by its mole fraction times the total pressure of the mixture
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 :B

Discussion

23.	Assertion : The radius of the first orbit of hydrogen atom is 0.529 Å. Reason : Radius for each circular orbit (r_n)=0.529 Å (n^2//Z) , where r=1,2,3 and Z = atomic number.
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 :Both assertion and reason are true and reason is the correct explanation of assertion. RADIUS , `r=(n^2h^2)/(4pie^2 mZ)=n^2/Z xx 0.529 Å.r_n` also increases INDICATING a greater SEPARATION between the orbit and the NUCLEUS

Discussion

24.	Assertion : The pressure of a given mass of a gas is directly proportional to the temperature on kelvin scale at constant volume Reason : With the increase in temperature, the average kinetic energy and hence the average velocity of the molecule increases
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 :A

Discussion

25.	Assertion : The pressure of a gas is inversely proportional to the volume at contant temperature and n Reason : The gas volume is directly proportional to n at constant temperature and pressure
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 :B

Discussion

26.	Assertion. The plots of probability density and radial probability function versus distance r from the nucleus for any particular orbital are not identical Reason. Probability density is Psi^(2) whereas radial probability function represents probability of finding the electron in a shell of thickness dr.
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 :The PLOTS are not identical (see Fig. 2.27 and 2.44) The PROBABILITY density `(Psi^(2))` is along the radial distance whereas radial probability FUNCTION `(4pi r^(2) Psi^(2))` is the probability in a shell of thickness dr. Hence R is the correct explanation of A.

Discussion

27.	Assertion: The pK_(a) of acetic acid is lower than that of phenol Reason: Phenoxide ion is more resonance stabilised.
Answer» If both ASSERTION and REASON are TRUE and reason is a correct EXPLANATION of assertion. If both assertion and reason are true but reason is not a correct explanation of assertion. If assertion is true but reason is false. If assertion and reason both are false. Answer :C

Discussion

28.	Assertion : The packing efficiency is maximum for the fcc structure. Reason : The coordination is 12 in fcc struture.
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 explanation . Fcc is a close PACKED structure.

Discussion

29.	Assertion: The pH of acid rain is less than 5.6.Reason: Carbon dioxide present in the atmosphere dissolves in rain water and forms carbonic acid.
Answer» Both ASSERTION and REASON are correct and Reason is the correct EXPLANATION of Assertion Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion. Both Assertion and Reason are incorrect Assertion is not correct but Reason is correct. Answer :B

Discussion

30.	Assertion. The pH at the end point of any acid-base titration is always 7. Reason. The aqueous solution of a salt is always neutral.
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 aasertion is true, but reason is false. If both assertion and reason are false. Solution :Correct A. ThepH at the end point of only a strong acid with strong BASE is 7. Correct R. The AQUEOUS solution of a salt of strong acid and strong base is neutral. In other CASES, it depends upon the nature of the salt formed.

Discussion

31.	Assertion: The order of stability of carbocations is 3^(@) gt 2^(@) gt 1^(@) Reason: Carbon atom in carbocation is in sp^(3) state of hybridisation.
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 ORDER of STABILITY of carbocations is `3^(@) gt 2^(@) gt 1^(@)`. Carbon atom of carbocation is in `SP^(2)` hybridisation state.

Discussion

32.	Assertion :The oxidation number of fluorine in all its compounds is always-1 Reason :Fluorine is a highly reactive element .
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 only way to get F_(2) form F^(-) is to oxidise electrolytically. Reason : The recovery of halogens from their halides requires an oxidation process.
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 :Chemical means ( OXIDISING agents LIKE `KMnO_(4), K_(2)Cr_(2)O_(7), MnO_(2)`) are available to oxidise `CL^(-)`, `Br^(-)` and `I^(-)`. As fluorine itselt isa strongest oxidising agent, there is no way to convert `F^(-)` to `F_(2)` by chemical means, hence it is oxidised electrolytically.

Discussion

34.	Assertion. TheO-O bond length in H_(2)O_(2) is shorter than that of O_(2)F_(2) Reason. H_(2)O_(2) is an ionic compound.
Answer» Solution :Correct assertion. The O-O bond length in `H_(2)O_(2)` is much longer than that in `O_(2)F_(2)` . Correct reason . The lone PAIR of electrons on the O atoms are STRONGLY ATTRACTED by the electronegative F atoms. As a result , lone pairlone pair REPULSION of the TWO oxygen atoms is far less in `O_(2)F_(2)` than in `H_(2)O_(2)` . As a result, O-O bond length in `O_(2)F_(2)` (1.22 Å) is much shorter than in `H_(2)O_(2) `(1.48 Å)

Discussion

35.	Assertion The number of tetrahedral voids is double the number of octahedral voids. Reason(R)The size of the tetrahedral void is half of that of theoctahedral void.
Answer» Both A and R are TRUE and R is THECORRECT EXPLANATION of A Both A andR 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

36.	Assertion : The number of oxygen atoms in 16 g of oxygen and 16 g of ozone is same . Reason : Each of the species represent 1g atom of oxygen .
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

37.	Assertion: The nucleophilic substitution of vinyl chloride is difficult than ethyl chloride. Reason: Vinyl chloride undergoes only addition reactions.
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

38.	Assertion: The nucleophilic substitution of vinyl chloride is difficult than ethyl chloride. Reason : Vinyl group is electron donating group.
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 :C

Discussion

39.	Assertion : The normal boiling point of water is 100 C^(@) and standard boiling point of water is 99.6 C^(@) .Reason : The temperature at which vapour pressure of liquid is equal to the external pressure is called boiling temperature at that pressure .
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 :At 1 atm pressure, BOILING temperature is called normal boiling point and if pressure is 1 BAR then the boiling point is called standard boiling point of the liquid. 1 bar pressure is slightly less than 1 atm pressure therefore, standard boiling point of the liquid is slightly LOWER than the normal boiling point.

Discussion

40.	Assertion: The name of the hybrocarbon (CH_(3))_(2)CHCH_(2)CH_(2)CH(CH_(3))CH_(2)CH_(3) is 2,5-dimethylheptane and not 3,6-dimethylheptane. Reason: Numbering should be done in such a way that sum of the locants on the parennt chain is lowest possible number.
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

41.	Assertion . The mobility of sodium ion is lower than that of potassium ion . Reason . The ionic mobilities depend upon the effective radius of the ion .
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 . Because of smaller size , the extent of hydration of `NA^(+)` ions is HIGHER than that of `K^(+)` ions . As a result , effective radius and hence the mass of HYDRATED `Na^(+)` ions is higher than that of `K^(+)` ions and , therefore , their mobility is LOWER than that of `K^(+)` ions .

Discussion

42.	Assertion: The melting and boiling points of the alkali metals are low. Reason: Alkali metals have weak metalli bonding.
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 :Alkali metals have weak METALLIC bonding DUE to the presence of only a SINGLE VALENCE electron in them.

Discussion

43.	Assertion : The maximum number of electrons in the shell with principle quantum number n is equal to 2n^(2). Reason : Two electrons can have the same value of three quantum numbers n, l and m_(l), but must have the opposite spin quantum number.
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

44.	Assertion:The major product obtained in the reaction of HBr with propene is 2-bromopropane.Reason : 2^@carbocations are more stable than 1^@carbocations.a. If both Assertion and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion.b.f both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion.c.Assertion is CORRECT but Reason is INCORRECT.d.If Assertion is INCORRECT but Reason is CORRECT.
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

45.	Assertion : The lowest hypothetical or imaginary temperature at which gases are supposed to occupy zero volume is called absolute zero .Reason : Volume of the gas at-273 . 15 C^(@) becomes zero i.e. gas does not exist at this temperature .
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 . ANSWER :A

Discussion

46.	Assertion: The ionisation energy of N is more than that of O. Reason: Electronic configuration of N is more stable due to half filled 2p orbitals.
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 :A

Discussion

47.	Assertion : The IUPAC name of CH_(3)CH=CH-C CH is pent-2-ene-4-yne and not pent-3-en-1-yne. Reason : While deciding the locants for double bond and triple bonds, lowest locant rule for multiple bonds is followed.
Answer» If both ASSERTION and REASON are TRUE and the reason is the CORRECT explanation of the assertion. If both the assertion and reason are true but the reason is not the correct explanation of assertion. If the assertion is true but reason is false. If assertion is false but reason is true. Answer :d

Discussion

48.	Assertion (A) Three states of matter are the result of balance between intermolecular forces and thermal energy of the molecules. Reason (R) Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep tham apart.
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 and Reason is the CORRECT explanation of the Assertion.

Discussion

49.	Assertion . The HF_(2)^(-) ion exists in the solid state and also in the liquid state but not in aqueous solution . Reason . The magnitue of hydrogen bonds inbetween HF -HF moelcules is weaker than that inbetween HF and H_(2) Omolecules.
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 :R is the correct explanation of A .

Discussion

50.	Assertion. The heat of combustion found by using bomb calorimeter gives the value of internal energy change DeltaU and not enthalpy change DeltaH. Reason.In a closed vessl,DeltaU = DeltaHonly ifpressure inside the calorimeter remains constant.
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 :a

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Assertion : The total number of atoms present in a simple cubic unit cell is one. Reason : Simple cubic unit cell has atoms at its corners , each of which is shared between eight adjacent unit cells.

Assertion. The temperature in the stratosphere increases with altitude Reason. Ozone present absorbs the ultraviolet radiation.

Assertion. The temperature of a gas does notchange when it undergoes an adiabatic expansion. Reason . During an adiabatic expansion of a real gas, the internal energy of the gas remains constant.

Assertion. The sum of the radii of Na^+ and Cl^- ions in NaCl crystal is 281 pm. Hence, edge of the unit cell is 281 pm Reason. Edge of the unit cell is the distance between the centres of Na^+ and Cl^- ions touching each other .

Assertion : The strength of haloacids increases in the order : HIltltBHrltltHClltltHF Reason : Strength of acid HA depends only on the electronegatively difference between H and A.

Assertion : The standard unit of expressing mass of atoms is called 'u' Reason :'u' represents unit mass.

Assertion : the spectrum of He^(+) is expected to be similar to that of hydrogen Reason : He^(+) is also one electron system

Assertion : The spectrum of He^(+) is expected to be similar to that of hydrogen Reason : He^(+) is also one electron system.

Assertion The spectrum of He is expected to be similar to that of hydrogen Reason: He^(+) is also one electron system

Why are the solutions of alkali metal atoms in liquid ammonia blue coloured and highly conducting?

Assertion : The solubility of most salts in water increases with rise of temperature. Reason : For most of the ionic compounds, Delta_("sol")H^(@) is positive and the dissociation process is endothermic.

Assertion: The SI unit of force is kg m^(2) s^(-2) Reason: Force = mass x acceleration. The SI unit of mass is kg and that of acceleration is ms^(-2).

Assertion: The second substituent may enter the mono-substituted benzene ring at either ortho, para or at meta position. Reason: The position of the incoming group is determined by the natrue fo the group present in monosubstituted benzene ring.

Assertion : The S-S-S bond angle in S_8 molecule is 105^@ Reason:S_8 has a V-shape.

Assertion . The resonance hybrid is more stable than any of the contributing structure . Reason . The contributing structures contain the same number of umpaired elelctrons and have the real existance.

Assertion : The relative proportion of atoms of THtium and Protium is 1 : 10^(17) Reason : The property responsible for the low proportion of Tritium is its non-radioactivity.

Assertion: The relative proportion of Tritium and Protium is 1: 10^17 Reason: The property responsible for the low proportion of Tritium is its non-radioactivity.

Assertion: The reaction, C_(2)H_(5)Br +2Na+C_(2)H_(5)Br to C_(4)H_(10)+2NaBr is known as Wurtz reaction. Reason: The reaction is carried out in presence of dry ether.

Gases deviate from the ideal gas behaviour because their molecules

Assertion : The reaction 2NO (g) + O_(2) (g) hArr 2NO_(2)(g) is favoured in the forward direction with increase ofpressure. Reason : The reaction is exothermic.

Assertion:The reactant which is present in large amount limits the amount of product formed is called limiting reagent. Reason : Amount of product formed does not depend upon the amount of reactants taken.

Assertion : The reacting gases combine in volumes that are ratios of small whole number Reason : The partial pressure of a gas in a mixture is given by its mole fraction times the total pressure of the mixture

Assertion : The radius of the first orbit of hydrogen atom is 0.529 Å. Reason : Radius for each circular orbit (r_n)=0.529 Å (n^2//Z) , where r=1,2,3 and Z = atomic number.

Assertion : The pressure of a given mass of a gas is directly proportional to the temperature on kelvin scale at constant volume Reason : With the increase in temperature, the average kinetic energy and hence the average velocity of the molecule increases

Assertion : The pressure of a gas is inversely proportional to the volume at contant temperature and n Reason : The gas volume is directly proportional to n at constant temperature and pressure

Assertion: The pK_(a) of acetic acid is lower than that of phenol Reason: Phenoxide ion is more resonance stabilised.

Assertion : The packing efficiency is maximum for the fcc structure. Reason : The coordination is 12 in fcc struture.

Assertion: The pH of acid rain is less than 5.6.Reason: Carbon dioxide present in the atmosphere dissolves in rain water and forms carbonic acid.

Assertion. The pH at the end point of any acid-base titration is always 7. Reason. The aqueous solution of a salt is always neutral.

Assertion: The order of stability of carbocations is 3^(@) gt 2^(@) gt 1^(@) Reason: Carbon atom in carbocation is in sp^(3) state of hybridisation.

Assertion :The oxidation number of fluorine in all its compounds is always-1 Reason :Fluorine is a highly reactive element .

Assertion : The only way to get F_(2) form F^(-) is to oxidise electrolytically. Reason : The recovery of halogens from their halides requires an oxidation process.

Assertion. TheO-O bond length in H_(2)O_(2) is shorter than that of O_(2)F_(2) Reason. H_(2)O_(2) is an ionic compound.

Assertion The number of tetrahedral voids is double the number of octahedral voids. Reason(R)The size of the tetrahedral void is half of that of theoctahedral void.

Assertion : The number of oxygen atoms in 16 g of oxygen and 16 g of ozone is same . Reason : Each of the species represent 1g atom of oxygen .

Assertion: The nucleophilic substitution of vinyl chloride is difficult than ethyl chloride. Reason: Vinyl chloride undergoes only addition reactions.

Assertion: The nucleophilic substitution of vinyl chloride is difficult than ethyl chloride. Reason : Vinyl group is electron donating group.

Assertion : The normal boiling point of water is 100 C^(@) and standard boiling point of water is 99.6 C^(@) .Reason : The temperature at which vapour pressure of liquid is equal to the external pressure is called boiling temperature at that pressure .

Assertion: The name of the hybrocarbon (CH_(3))_(2)CHCH_(2)CH_(2)CH(CH_(3))CH_(2)CH_(3) is 2,5-dimethylheptane and not 3,6-dimethylheptane. Reason: Numbering should be done in such a way that sum of the locants on the parennt chain is lowest possible number.

Assertion . The mobility of sodium ion is lower than that of potassium ion . Reason . The ionic mobilities depend upon the effective radius of the ion .

Assertion: The melting and boiling points of the alkali metals are low. Reason: Alkali metals have weak metalli bonding.

Assertion : The maximum number of electrons in the shell with principle quantum number n is equal to 2n^(2). Reason : Two electrons can have the same value of three quantum numbers n, l and m_(l), but must have the opposite spin quantum number.

Assertion : The lowest hypothetical or imaginary temperature at which gases are supposed to occupy zero volume is called absolute zero .Reason : Volume of the gas at-273 . 15 C^(@) becomes zero i.e. gas does not exist at this temperature .

Assertion: The ionisation energy of N is more than that of O. Reason: Electronic configuration of N is more stable due to half filled 2p orbitals.

Assertion : The IUPAC name of CH_(3)CH=CH-C CH is pent-2-ene-4-yne and not pent-3-en-1-yne. Reason : While deciding the locants for double bond and triple bonds, lowest locant rule for multiple bonds is followed.

Assertion (A) Three states of matter are the result of balance between intermolecular forces and thermal energy of the molecules. Reason (R) Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep tham apart.

Assertion . The HF_(2)^(-) ion exists in the solid state and also in the liquid state but not in aqueous solution . Reason . The magnitue of hydrogen bonds inbetween HF -HF moelcules is weaker than that inbetween HF and H_(2) Omolecules.

Assertion. The heat of combustion found by using bomb calorimeter gives the value of internal energy change DeltaU and not enthalpy change DeltaH. Reason.In a closed vessl,DeltaU = DeltaHonly ifpressure inside the calorimeter remains constant.