52671 + Interview Questions in Chemistry in Class 11

1.	Statues coated with white lead on long exposure to atmosphere turn black and their original colour can be restored on treatment with H_2 O_2 . Why?
Answer» Solution :On long exposure to ATMOSPHERE, white lead gets converted to BLACK`PbS` due to action of `H_2S` present in the atmosphere. `PbO_2 + underset("From atmosphere")(H_2 S) + underset("Black")(PbS) + 2H_2 O` As a result, statues turn black. On TREATMENT of these black statues with `H_2O_2` the black PbS gets oxidised to `PbSO_4` and their COLOUR is restored. `PbS + H_2 O_2 to PbSO_4 + 4H_2 O`

Discussion

2.	Statues and monuments in India are affected by acid rain. How ?
Answer» Solution :A large numbers of industris and power plants are around near the area of Taj Mahal. Which uses poor quality of COAL, KEROSENE and firewood because of this the air around the Taj Mahal contains fairly high level of sulphur and NITROGEN oxides. This resulting in acid rain which reacts with marble of Taj Mahal. `CaCO_3 + H_2 SO_4 to CaSO_4 + H_2 O + CO_2` Thus, this wonderful monument that has attracted PEOPLE from around the WORLD. As a result, the monument is being slowly disfigured and the marble is getting discoloured and lustreless.

Discussion

3.	Staticisotopes of Hydrogenand writethe no ofprotonElectronNeutronin them .
Answer» SOLUTION :

Discussion

4.	Statements in Column I are labelled as A,B,C and D whereas the statements in Column II are labelled as p,q,r and s . The answers to these question are to be appropriately bubbled as illustrated in the following example. If the correct matches are A-p, A-S B-q, B-r, C-p , C-q and D-p then correctly labelled 4xx4 matrix should look like the following {:("Column I",,,,"Column II"),((A)N_(2)(g)+3H_(2)(g) hArr 2NH_(3)(g), Delta H=-92.5 kJ,,,,"(p) K increases with increase in temperature"),((B)N_(2)(g) +O_(2)(g) hArr 2NO_(2)(g) , Delta H=+180 kJ,,,,"(q) K decreases with increase in temperature"),((C )A(g)+B(g) hArr 2C(g)+D.(g) , Delta H =+ve,,,,"(r ) Pressure has no effect. "),((D)PCl_(5) hArr PCl_(3)+Cl_(2) , Delta H=+ve,,,,"(s) Catalyst has no effect"):}
Answer» ANSWER :`(##DIN_OBJ_CHM_V01_C2_2_E01_246_A01##)`

Discussion

5.	Statements in Column I are labelled as A, B, C and D whereas thestatementsin Column II are labelled as p, q, r and s. The answers to these questions are to be appropriately bubbled as illustrated below in the following example. If the correct matches are A-p, A-s, B-q, B-r, C-p, C-q and D-p, theircorretly labelled 4times 4 matrix should look like : {:(,"Column-I",,"Column-II",),((A),"Hexagonal close packing (hcp)",p.,"Iron",),((B),"Cubic close packing (ccp)",q.,52%,),((C),"Body centred cubic)bcc)",r.,68%,),((D),"Simple cubic",s.,"74%",):}
Answer» ANSWER :`(##DIN_OBJ_CHM_V01_C3_2_E01_215_A01##)`

Discussion

6.	Statements in Column I are labelled as A, B, C and D whereas thestatementsin Column II are labelled as p, q, r and s. The answers to these questions are to be appropriately bubbled as illustrated below in the following example. If the correct matches are A-p, A-s, B-q, B-r, C-p, C-q and D-p, theircorretly labelled 4times 4 matrix should look like : {:(,"Column-I",,"Column-II",),((A),"Simple cubic and face centred cubic",p.,"have these cell parameters a=b=c and " alpha=beta=gamma,),((B),"Cubic and rhombohedral",q.,"are two crystal systems",),((C),"Cubic and tetragonal",r.,"has only two crystallographic angles of "90^(@)C,),((D),"hexagonal and monoclinic",s.,"belong to the same crystal system.",):}
Answer» ANSWER :`(##DIN_OBJ_CHM_V01_C3_2_E01_213_A01##)`

Discussion

7.	Statements in Column I are labelled as A, B, C and D whereas thestatementsin Column II are labelled as p, q, r and s. The answers to these questions are to be appropriately bubbled as illustrated below in the following example. If the correct matches are A-p, A-s, B-q, B-r, C-p, C-q and D-p, theircorretly labelled 4times 4 matrix should look like : {:(,"Column-I",,"Column-II",),((A),"Ionic solids",p.,"Dry ice",),((B),"Molecular solids",q.,"Brass",),((C),"Covalent solids",r.,"Generally insulators",),((D),"Metallic solids",s.,"Generally have low melting points",):}
Answer» ANSWER :`(##DIN_OBJ_CHM_V01_C3_2_E01_214_A01##)`

Discussion

8.	Statements in Column I are labelled as A, B, C and D whereas thestatementsin Column II are labelled as p, q, r and s. The answers to these questions are to be appropriately bubbled as illustrated below in the following example. If the correct matches are A-p, A-s, B-q, B-r, C-p, C-q and D-p, theircorretly labelled 4times 4 matrix should look like : {:(,"Column-I",,"Column-II",),((A),"NaCl",p.,"Crystalline",),((B),"p-type semiconductor",q.,"Doping",),((C),"n-type semiconductor",r.,"holes are responsible for movement of current",),((D),"Graphite",s.,"electrons are responsible for movement of current",):}
Answer» ANSWER :`(##DIN_OBJ_CHM_V01_C3_2_E01_212_A01##)`

Discussion

9.	Statements-I: Unlike alkenes and alkynes benzene undergoes substitution reactions rather than addition reaction under normal conditions. Statements-II: Because of the delocalisation of electrons a strong i bond is formed which makes the molecule stable.
Answer» STATEMENT -I and II are CORRECT and statement-II is correct EXPLANATION of statement-I. Statement-I and II are correct but statement-II is not correct explanation of statement-I Statement-I is correct but statement - II is WRONG. Statement-I is wrong but statement - II is correct. Solution :Statement -I and II are correct and statement-II is correct explanation of statement-I.

Discussion

10.	Statements I : Ionisation energy of fluorine is greater than oxygen.Statement II : On moving across a period ,nuclear charge increases
Answer» Both the STATEMENTS are individually true and II is the correct explanation of I. Both the statements are individually true and II is not the correct explanation of I. Statement I is correct and II is false Statement I is false and II is true Answer :a

Discussion

11.	Statements I : Noble gases have zero electron gain enthlpy.Statement II : An atom with stable electronic configuration has greater tendency to gain electron.
Answer» Both the statements are INDIVIDUALLY CORRECT and II is the correct EXPLANATION of I Both the statements are individually correct and II is not the correct explanation of I Statement I is correct and IIis wrong Statement Iis wrong and II is correct Answer :C

Discussion

12.	Statements and reasons are given. Choose the correct option form the following. (Q.43, 44, 45) Statement : Enthalpy of formation of gaseous oxygen molecule is zero at 1 atm pressure and 298 K. Reason : Enthalpy of formation of oxygen molecule is zero for the same situation.
Answer» Statement and reason both are correct and correct EXPLANATION of statement is GIVEN by reason. Statement and reason both are correct but correct explanation of statement is not given by reason. Statement is correct but reason is wrong. Statement and reason both are wrong. Answer :C

Discussion

13.	Statements and reasons are given. Choose the correct option form the following. (Q.43, 44, 45) Statement : Chlorine gas become solid at absolute zero temperature but its entropy will be zero. Reason : Chlorine has strong small and its difficult to correct it into solid.
Answer» STATEMENT and REASON both are CORRECT and correct explanation of statement is given by reason. Statement and reason both are correct but correct explanation of statement is not given by reason. Statement is correct but reason is wrong. Statement and reason both are wrong. Answer :B

Discussion

14.	Statements and reasons are given. Choose the correct option form the following. (Q.43, 44, 45) Statement : Absorbed energy becomes zero when ideal gas is expand in vacuum. in isothermic process. Reason : Volume occupied by molecules is zero.
Answer» STATEMENT and reason both are CORRECT and correct EXPLANATION of statement is given by reason. Statement and reason both are correct but correct explanation of statement is not given by reason. Statement is correct but reason is wrong. Statement and reason both are wrong. Answer :C

Discussion

15.	Statement : Water is added to electrolyte of aqueous solution then molar conductivity increases. Reason : Dissociation of electrolytic substance decreases when electrolyte is added to aqueous solution.
Answer» Statement and reason both are correct and reason GIVES proper explanation of statement. Statement and reason both are RIGHT bụt reason is not explanation of statement. Statement is correct but reason is WRONG. Statement is wrong but reason is correct. Answer :C

Discussion

16.	Statement (S) : There is no geometrical isomers for CH_(2)=CHCl. Reason (R) : There is only one pi-bond exist between two carbon of CH_(2)=CHCl.
Answer» Both statement (S) and REASONS (R) are true. And (R) gives COMPLETE explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and Reason (R) are wrong Statement (S) is wrong and reason (R) is right Answer :B

Discussion

17.	Statement The atomic weight of an element is given by Dulong Petit's law: at.wt.xxsp. heat (cal//mole) cong6.4. Explanation The formula is valid for metals only and not for all elements.
Answer» `S` is correct but `E` is WRONG. `S` is wrong but `E` is wrong. Both `S` and `E` are correct and `E` is correct explanation of `S`. Both `S` and `E` are correct but `E` is not correct explanation of `S. Solution :DULONG PETIT's LAW is valid for metals only. Also it is `at.wt.xxsp`. Heat `(cal//g) cong 6.4`

Discussion

18.	Statement (S) : Trans ethane is more stable than cis ethane. Reasons (R) : Distortion is present in ethane but it is not present in trans.
Answer» Both STATEMENT (S) and REASONS (R) are true. And (R) GIVES COMPLETE EXPLANATION of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and Reason (R) are wrong Statement (S) is wrong and reason (R) is right Answer :A

Discussion

19.	Statement (S) : Polarity of cis isomer is more with respect to trans isomers. Reason (R) : Cis and trans isomers are geometrical isomers.
Answer» Both statement (S) and REASONS (R) are true. And (R) GIVES complete EXPLANATION of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and REASON (R) are wrong Statement (S) is wrong and reason (R) is right Answer :B

Discussion

20.	Statement (S) : Substitution reactions of benzene is quite difficult with respect toaddition reaction. Reason (R) : Addition products does not possess resonating stability and aromatic.
Answer» Both statement (S) and Reasons (R) are TRUE. And (R) GIVES complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and REASON (R) are wrong Statement (S) is wrong and reason (R) is right Answer :A

Discussion

21.	Statement (S) : Nitration of toluene is occur on ortho and para position. Reason (R) : -CH_(3) group in toluene is ortho and para directing in nature.
Answer» Both statement (S) and Reasons (R) are true. And (R) GIVES complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and REASON (R) are wrong Statement (S) is wrong and reason (R) is right Answer :A

Discussion

22.	Statement (S) : Isomers are not possible for ethane. Reason (R) : There is a double bond between two carbon atom.
Answer» Both statement (S) and Reasons (R) are true. And (R) gives complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and REASON (R) are wrong Statement (S) is wrong and reason (R) is right Answer :C

Discussion

23.	Statement (S) : For nitration of chlorobenzene more heating is required in comparision of benzene. Reason (R) : -Cl groups is deactivatorin chloro-benzene.
Answer» Both statement (S) and Reasons (R) are true. And (R) gives COMPLETE explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and REASON (R) are wrong Statement (S) is wrong and reason (R) is right Answer :A

Discussion

24.	Statement (S) : For chlorination of methane constant ultraviolet rays are required. Reason (R) : In termination step of reaction mechanism free radicals are attached.
Answer» Both statement (S) and REASONS (R) are TRUE. And (R) GIVES complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and Reason (R) are wrong Statement (S) is wrong and reason (R) is right Answer :A

Discussion

25.	Statement (S) : For chlorination of benzene FeCl_(3) is also required along with Cl_(2). Reason (R) : Chlorination is carried out by Cl of FeCl_(3).
Answer» Both statement (S) and REASONS (R) are TRUE. And (R) gives complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and Reason (R) are wrong Statement (S) is RIGHT and Reason (R) is wrong Answer :D

Discussion

26.	Statement (S) : Ethene can perform electrophilic reactions easily with respect to ethane. Reason (R) : There is no pi- electron in ethane.
Answer» Both statement (S) and Reasons (R) are TRUE. And (R) gives complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and REASON (R) are wrong Statement (S) is wrong and reason (R) is right Answer :B

Discussion

27.	Statement (S) : Electrophilic susbtitution reaction of benzene is very difficult. Reason (R) : Delocalized 3pi electron clouds are presenet in benzene ring.
Answer» Both statement (S) and REASONS (R) are TRUE. And (R) GIVES complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and Reason (R) are wrong Statement (S) is wrong and reason (R) is right Answer :B

Discussion

28.	Statement (S) : Cis and trans geometrical isomers of CH_(3)CH = CHCH_(3) is possible. Reason (R) : Free radical rotation surrounding carbon-carbon double bond is not possible in CH_(3)CH=CHCH_(3).
Answer» Both STATEMENT (S) and REASONS (R) are true. And (R) GIVES complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and REASON (R) are wrong Statement (S) is wrong and reason (R) is right Answer :A

Discussion

29.	Statement (S) : Both -OH and -NH_(2) are m-directing in nature. Reason (R) : Both -OH and -NH_(2) donate their lone pair electrons to the benzene ring in resonance.
Answer» Both STATEMENT (S) and Reasons (R) are true. And (R) gives complete EXPLANATION of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and Reason (R) are WRONG Statement (S) is wrong and reason (R) is right Answer :D

Discussion

30.	Statement (S) : Chlorination of toluene gives mixtures of ortho and para chloro toluene. Reason (R) : -CH_(3) group is presenet in toluene.
Answer» Both STATEMENT (S) and Reasons (R) are true. And (R) GIVES COMPLETE explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and Reason (R) are wrong Statement (S) is wrong and reason (R) is right Answer :B

Discussion

31.	Statement (S) : -CH_(3) group possess ortho and para directing effect. Reason (R) : -CH_(3) group donate its electro pair and negative charge on ortho and para position.
Answer» Both statement (S) and REASONS (R) are TRUE. And (R) gives complete explanation of (S). Both statement (S) and Reasons (R) are true. But (R) does not gives complete explanation of (S). Both statement (S) and Reason (R) are wrong Statement (S) is wrong and reason (R) is right Answer :A

Discussion

32.	Statement : Oxygen has liberated on anode when electricity pass through aqueous solution of Na_(2)SO_(4) in presence of it electrode. Reason : 2SO_(4(aq))^(2-)hArrS_(2)O_(8(aq))^(2-)+2e^(-) 2H_(2)O_((l))hArrO_(2(g))+4H_((aq))^(+)+4e^(-) standard potential of equation.
Answer» STATEMENT and reason both are correct and reason gives PROPER EXPLANATION of statement. Statement and reason both are RIGHT bụt reason is not explanation of statement. Statement is correct but reason is WRONG. Statement is wrong but reason is correct. Answer :A

Discussion

33.	Statement-l: The magnetic moment of para hydrogen is zero. Statement-II: The spins of two hydrogen atoms in pam Il, molecule neutralise each other.
Answer» STATEMENTS I UND II are correct and Statement-II is the correct EXPLANATION of statement-I. Statements and I are correct but Statement-IL is not the correct explanation of statement Statement-l is correct but Statement. Il is WRONG, Statement-I is wrong but Statement-Il is correct. Answer :A

Discussion

34.	Statement-l: Internal energy of a system is an extensive property. Statement-II: Internal energy depends on the amount of the substances present in the system.
Answer» Statement-I and II are CORRECT and Statement-II is the correct EXPLANATION of Statement-I Statement-I and II are correct but Statement-II is not the correct explanation of Statement-I Statement-Iis correct and Statement-II is WRONG Statement-I is wrong but Statement-II is correct ANSWER :A

Discussion

35.	Statement-l: Fluoro acetic acid is stronger acid than acetic acid. Statement-II: Fluorine has high electronegativity and it is facilitate to dissociate the O-H bond easily.
Answer» Statement-I and II are CORRECT and statement-II is correct EXPLANATION of statement-I. Statement-I and II are correct but statement-II is not correct explanation of statement-I. Statement-I is correct but statement-II is WRONG. Statement-I is wrong but statement-II is correct ANSWER :A

Discussion

36.	Statement-I: ZrH_(2) is a non-stoichiometric hydride Statement-II: The composition of ZrH_(2) is exact same as its chemical formula.
Answer» If both STATEMENT-1 `&` Statement-II are True `&` the Statement-II is not a correct explanation of the Statement I. If both Statement-I `&` Statement-II are True but Statement-II is not a correct explanantion of the Statement-I. If Statement-I is True but the Statement-II is FALSE. If Statement-I is False but the Statement-II is True. Solution :N//A

Discussion

37.	Statement I : Value of COD is greater than BOD Statement II : Used oxygen is demanded by some chemicals for oxidation of inorganic and organic pollutants.
Answer» Both statement I and statement II are true and statement II EXPLAINS statement I Both statement I and statement II are true but statement II does not EXPLAIN statement I Statement I is true but statement II is false Both statement I and II are false. Answer :a

Discussion

38.	Statement -I unlike alkenes and alkynes benzene undergoes substitution reaction ratherthan additionreaction under normal condition Statement -IIbecause of the delocalisation of electrons a strong pibond is formed which makes the molecule stable
Answer» statement -I and II are correct statement -II is correct EXPLANATIN of statement -I statement -I and II are correct but statement -II is not correct EXPLANTION ofstatement -I statement -I is correct but statement-II is wrong statement-I is worngbut statement-II is correct Answer :a

Discussion

39.	Statement-I : The value of Boyle's temperature fora real gas is (T_(B) = (a)/(Rb)) Because Statement -2 : At Boyle's temperature, T_(B), real gases behave ideally over a long range of pressure
Answer» STATEMENT -1 is TRUE , statement -2 is true, statement-2 is a CORRECT explanation of statement-3 Statement-1 is true , statement -2 is true, statement-2 is not a correct explanation of statement -3 Statement-1 is true, statement-2 is FALSE Statement -1 is false, statement-2 is true Answer :B

Discussion

40.	Statement: I : The solubility of aldehydes and ketones in water decreases with increase of size of the alkyl groupStatement - :II: Alkyl groups are eletron releasing groups
Answer» Boththestatements are TRUE and statement- II is the CORRECT explanation of statement -I. Both STATEMENTS are true but statement -II is not the correct explanation of statement -I. Statement-I is true but statement -II is falsae Statement -I is FALSE but statement- II is true Answer :2

Discussion

41.	Statement I : The O-O bond length in H_2O_2 is shorter than that of O_2F_2 Statement II : H_2O_2 is an ionic compound.
Answer» Both STATEMENT I and II are TRUE but statement II EXPLAINS statement I Both statement I and II are true but statement II does not explains statement I Statement I is true but statement II is false. Both the STATEMENTS are false. Answer :D

Discussion

42.	STATEMENT -I :Thefollowing conversion can be done by usingNH_(2)-NH_(2)//KOH, Deltan ot byZn - Hg//con . HCl. STATEMENT -2 : Zn. Hg// HClcanaffect- OHgroup and shows aubstitution reaction.
Answer» STATEMENT-1is TRUE, Statement -2 is True , STAMENT -2 is a CORRECT EXPLANATION for Statement -I. STATEMENT-1is True, Statement -2 is True , Stament -2 is a correct explanation for Statement -I. Statement -1 isTrue, Statement -2 is False. Statement - 1 and Statement -2 both are Fals Answer :A

Discussion

43.	Statement I: The most common property of sea water and air is homogeneity. Statement II: The homogeneity implies uniform distribution of their constituents through the mixture.
Answer» Statement I and II are CORRECT and II is the correct EXPLANATION of I. STATEMENTS I and II are correct but II is not the correct explanation of I. Statement I is correct but II is wrong. Statement I is wrong but II is correct. Answer :A

Discussion

44.	Statement -:I : The B.P' s aldehydes and ketones are higher than those of ethers of comparable molecular masses.Statement -:II:Aldehydes and ketones undergo intermolecular association due to dipole -dipole interactions.
Answer» Boththestatements are TRUE and statement- II is the correct EXPLANATION of statement -I. Both STATEMENTS are true but statement -II is not the correct explanation of statement -I. Statement-I is true but statement -II is falsae Statement -I is false but statement- II is true Answer :1

Discussion

45.	Statement I: The dissolution of ammonium nitrate increase steeply with increase in temperature. Statement II: The dissolution process of ammonium nitrate is endothermic in nature.
Answer» STATEMENT I and II are correct and statement II is the correct EXPLANATION of statement I. Statement I and II are correct but II is not the correct explanation of I. Statement I is WRONG but II is wrong. Statement I is wrong but II is correct. ANSWER :A

Discussion

46.	Statement -I: The acetal formation with ketones does not respond to base catalysis . Statement-II The dehydration step has to be acid catalysed.
Answer» Boththestatements are true and statement- II is the correct explanation of statement -I. Both STATEMENTS are true but statement -II is not the correct explanation of statement -I. Statement-I is true but statement -II is falsae Statement -I is FALSE but statement- II is true Answer :1

Discussion

47.	STATEMENT -I :STATEMENT -2 :Polycarbonyl compound withalpha -Hgive intramolecular aldol condensation in alkaline medium , if it can form a stable ring.
Answer» STATEMENT-1is TRUE, Statement -2 is True , Stament -2 is a correct EXPLANATION for Statement -I. STATEMENT-1is True, Statement -2 is True , Stament -2 is a correct explanation for Statement -I. Statement -1 ISTRUE, Statement -2 is False. Statement - 1 and Statement -2 both are Fals Answer :D

Discussion

48.	Statement - I :- Sm^(3+), Dy^(3+) have same colour (yellow) Statement - II :- Both ions are having same nupaired electrons
Answer» Statement I is true, Statement II is true, Statement II is a CORRECT EXPLANATION of Statement I. Statement I is true, Statement II is true, Statement II is not the correct explanation of statement I Statement I is true, Statement II is FALSE. Statement I is false, Statement II is true. Answer :A

Discussion

49.	Statement-I: Pure zinc reacts slowly with sulphuric acid to produce hydrogen. Statement-II: Hydrogen produced initially forms and exteremely thin layer on zinc surface which prevents its dissolution in sulphuric acid.
Answer» If both Statement-1 `&` Statement-II are True `&` the Statement-II is not a CORRECT explanation of the Statement I. If both Statement-I `&` Statement-II are True but Statement-II is not a correct EXPLANANTION of the Statement-I. If Statement-I is True but the Statement-II is FALSE. If Statement-I is False but the Statement-II is True. Solution :N//A

Discussion

50.	Statement I : Productivity of eutrophic lake is maximum. Statement II : Cation is mainly due to adding of SO_(4)^(2-) and heavy metals.
Answer» Both STATEMENT I and statement II are true and statement II explains statement I Both statement I and statement II are true but statement II does not EXPLAIN statement I Statement I is true but statement II is false Both statement I and II are false. Answer :C

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Statues coated with white lead on long exposure to atmosphere turn black and their original colour can be restored on treatment with H_2 O_2 . Why?

Statues and monuments in India are affected by acid rain. How ?

Staticisotopes of Hydrogenand writethe no ofprotonElectronNeutronin them .

Statements-I: Unlike alkenes and alkynes benzene undergoes substitution reactions rather than addition reaction under normal conditions. Statements-II: Because of the delocalisation of electrons a strong i bond is formed which makes the molecule stable.

Statements I : Ionisation energy of fluorine is greater than oxygen.Statement II : On moving across a period ,nuclear charge increases

Statements I : Noble gases have zero electron gain enthlpy.Statement II : An atom with stable electronic configuration has greater tendency to gain electron.

Statements and reasons are given. Choose the correct option form the following. (Q.43, 44, 45) Statement : Enthalpy of formation of gaseous oxygen molecule is zero at 1 atm pressure and 298 K. Reason : Enthalpy of formation of oxygen molecule is zero for the same situation.

Statements and reasons are given. Choose the correct option form the following. (Q.43, 44, 45) Statement : Chlorine gas become solid at absolute zero temperature but its entropy will be zero. Reason : Chlorine has strong small and its difficult to correct it into solid.

Statements and reasons are given. Choose the correct option form the following. (Q.43, 44, 45) Statement : Absorbed energy becomes zero when ideal gas is expand in vacuum. in isothermic process. Reason : Volume occupied by molecules is zero.

Statement : Water is added to electrolyte of aqueous solution then molar conductivity increases. Reason : Dissociation of electrolytic substance decreases when electrolyte is added to aqueous solution.

Statement (S) : There is no geometrical isomers for CH_(2)=CHCl. Reason (R) : There is only one pi-bond exist between two carbon of CH_(2)=CHCl.

Statement The atomic weight of an element is given by Dulong Petit's law: at.wt.xxsp. heat (cal//mole) cong6.4. Explanation The formula is valid for metals only and not for all elements.

Statement (S) : Trans ethane is more stable than cis ethane. Reasons (R) : Distortion is present in ethane but it is not present in trans.

Statement (S) : Polarity of cis isomer is more with respect to trans isomers. Reason (R) : Cis and trans isomers are geometrical isomers.

Statement (S) : Substitution reactions of benzene is quite difficult with respect toaddition reaction. Reason (R) : Addition products does not possess resonating stability and aromatic.

Statement (S) : Nitration of toluene is occur on ortho and para position. Reason (R) : -CH_(3) group in toluene is ortho and para directing in nature.

Statement (S) : Isomers are not possible for ethane. Reason (R) : There is a double bond between two carbon atom.

Statement (S) : For nitration of chlorobenzene more heating is required in comparision of benzene. Reason (R) : -Cl groups is deactivatorin chloro-benzene.

Statement (S) : For chlorination of methane constant ultraviolet rays are required. Reason (R) : In termination step of reaction mechanism free radicals are attached.

Statement (S) : For chlorination of benzene FeCl_(3) is also required along with Cl_(2). Reason (R) : Chlorination is carried out by Cl of FeCl_(3).

Statement (S) : Ethene can perform electrophilic reactions easily with respect to ethane. Reason (R) : There is no pi- electron in ethane.

Statement (S) : Electrophilic susbtitution reaction of benzene is very difficult. Reason (R) : Delocalized 3pi electron clouds are presenet in benzene ring.

Statement (S) : Cis and trans geometrical isomers of CH_(3)CH = CHCH_(3) is possible. Reason (R) : Free radical rotation surrounding carbon-carbon double bond is not possible in CH_(3)CH=CHCH_(3).

Statement (S) : Both -OH and -NH_(2) are m-directing in nature. Reason (R) : Both -OH and -NH_(2) donate their lone pair electrons to the benzene ring in resonance.

Statement (S) : Chlorination of toluene gives mixtures of ortho and para chloro toluene. Reason (R) : -CH_(3) group is presenet in toluene.

Statement (S) : -CH_(3) group possess ortho and para directing effect. Reason (R) : -CH_(3) group donate its electro pair and negative charge on ortho and para position.

Statement : Oxygen has liberated on anode when electricity pass through aqueous solution of Na_(2)SO_(4) in presence of it electrode. Reason : 2SO_(4(aq))^(2-)hArrS_(2)O_(8(aq))^(2-)+2e^(-) 2H_(2)O_((l))hArrO_(2(g))+4H_((aq))^(+)+4e^(-) standard potential of equation.

Statement-l: The magnetic moment of para hydrogen is zero. Statement-II: The spins of two hydrogen atoms in pam Il, molecule neutralise each other.

Statement-l: Internal energy of a system is an extensive property. Statement-II: Internal energy depends on the amount of the substances present in the system.

Statement-l: Fluoro acetic acid is stronger acid than acetic acid. Statement-II: Fluorine has high electronegativity and it is facilitate to dissociate the O-H bond easily.

Statement-I: ZrH_(2) is a non-stoichiometric hydride Statement-II: The composition of ZrH_(2) is exact same as its chemical formula.

Statement I : Value of COD is greater than BOD Statement II : Used oxygen is demanded by some chemicals for oxidation of inorganic and organic pollutants.

Statement -I unlike alkenes and alkynes benzene undergoes substitution reaction ratherthan additionreaction under normal condition Statement -IIbecause of the delocalisation of electrons a strong pibond is formed which makes the molecule stable

Statement-I : The value of Boyle's temperature fora real gas is (T_(B) = (a)/(Rb)) Because Statement -2 : At Boyle's temperature, T_(B), real gases behave ideally over a long range of pressure

Statement: I : The solubility of aldehydes and ketones in water decreases with increase of size of the alkyl groupStatement - :II: Alkyl groups are eletron releasing groups

Statement I : The O-O bond length in H_2O_2 is shorter than that of O_2F_2 Statement II : H_2O_2 is an ionic compound.

STATEMENT -I :Thefollowing conversion can be done by usingNH_(2)-NH_(2)//KOH, Deltan ot byZn - Hg//con . HCl. STATEMENT -2 : Zn. Hg// HClcanaffect- OHgroup and shows aubstitution reaction.

Statement I: The most common property of sea water and air is homogeneity. Statement II: The homogeneity implies uniform distribution of their constituents through the mixture.

Statement -:I : The B.P' s aldehydes and ketones are higher than those of ethers of comparable molecular masses.Statement -:II:Aldehydes and ketones undergo intermolecular association due to dipole -dipole interactions.

Statement I: The dissolution of ammonium nitrate increase steeply with increase in temperature. Statement II: The dissolution process of ammonium nitrate is endothermic in nature.

Statement -I: The acetal formation with ketones does not respond to base catalysis . Statement-II The dehydration step has to be acid catalysed.

STATEMENT -I :STATEMENT -2 :Polycarbonyl compound withalpha -Hgive intramolecular aldol condensation in alkaline medium , if it can form a stable ring.

Statement - I :- Sm^(3+), Dy^(3+) have same colour (yellow) Statement - II :- Both ions are having same nupaired electrons

Statement-I: Pure zinc reacts slowly with sulphuric acid to produce hydrogen. Statement-II: Hydrogen produced initially forms and exteremely thin layer on zinc surface which prevents its dissolution in sulphuric acid.

Statement I : Productivity of eutrophic lake is maximum. Statement II : Cation is mainly due to adding of SO_(4)^(2-) and heavy metals.