CBSE Class 12 Chemistry 2022 question paper (56/2)

Maximum marks 35 · Time 2 hours · 3 sets

Try each question first, then open its model answer. Where the paper offers a choice, both questions are shown with OR between them.

Section A

2 marks each

Q.12 marks $How will you carry out the following conversions : (Any two) (i) Propanal to Propane (ii) Ethanal to But-2-enal (iii) Ethanoic acid to ethanamide$
Q.22 marks $\mathrm{N_2\,(g)} + 3\mathrm{H_2\,(g)} \longrightarrow 2\mathrm{NH_3\,(g)}$
Q.32 marks $\alpha$

Section B

3 marks each

Q.4 (a)3 marks $\mathrm{[NiCl_4]^{2-}}$
OR
Q.4 (b)3 marks $\mathrm{[Co(NH_3)_4(H_2O)Cl]Cl_2}$
Q.53 marks $\mathrm{Zn\,(s)} \mid \mathrm{Zn^{2+}}\,(0{\cdot}01\ \mathrm{M}) \parallel (0{\cdot}001\ \mathrm{M})\ \mathrm{Ag^{+}} \mid \mathrm{Ag\,(s)}$
Q.6 (a)3 marks $\mathrm{C_6H_5CHO} \xrightarrow[273-283\ \mathrm{K}]{\mathrm{HNO_3 + H_2SO_4}}$
OR
Q.6 (b)3 marks $(i) Oxidation of propanal is easier than propanone. Why ? (ii) How can you distinguish between Acetophenone and Benzophenone ? (iii) Draw the structure of the following derivative : 2,4-Dinitrophenylhydrazone of Propanone$
Q.73 marks $t_{1/2}$
Q.8 (a)3 marks $Write three differences between Lyophobic sol and Lyophilic sol.$
OR
Q.8 (b)3 marks $(i) Write the dispersed phase and dispersion medium of 'milk'. (ii) What is the cause of Brownian movement in colloidal particles ? (iii) Why does physisorption decrease with increase in temperature ?$

Q.93 marks

\mathrm{E}^{\ominus}_{\mathrm{M^{2+}/M}}

Q.10 (a)3 marks $Write the equation involved in the following reactions : (i) Rosenmund reduction (ii) Etard reaction (iii) Stephen reaction$
OR
Q.10 (b)3 marks $\mathrm{CH_3COOH}$
Q.113 marks $Account for the following : (i) Transition metals and their compounds show catalytic activities. (ii) Zn, Cd and Hg are non-transition elements. (iii) Zr and Hf are of almost identical atomic radii.$

$\mathrm{E}^{\ominus}_{\mathrm{M^{2+}/M}}$	Cr	Mn	Fe	Co	Ni	Cu	Zn
	$-\,0{\cdot}91$	$-\,1{\cdot}18$	$-\,0{\cdot}44$	$-\,0{\cdot}28$	$-\,0{\cdot}25$	$+\,0{\cdot}34$	$-\,0{\cdot}76$

Section C

Amines constitute an important class of organic compounds derived by replacing one or more hydrogen atoms of ammonia molecule by alkyl/aryl groups. Amines are usually formed from nitro compounds, halides, amides, etc. They exhibit hydrogen bonding which influences their physical properties. Alkyl amines are found to be stronger bases than ammonia. In aromatic amines, electron releasing and withdrawing groups, respectively increase and decrease their basic character. Reactions of amines are governed by availability of the unshared pair of electrons on nitrogen. Influence of the number of hydrogen atoms at nitrogen atom on the type of reactions and nature of products is responsible for identification and distinction between primary, secondary and tertiary amines. Reactivity of aromatic amines can be controlled by acylation process.
Q.12 (i)1 mark $Why does aniline not give Friedel-Crafts reaction ?$
Q.12 (ii)1 mark $\mathrm{pK_b}$
Q.12 (iii)1 mark $\mathrm{CH_3CH_2NH_2}$
Q.12 (iv) (a)2 marks $\mathrm{C_6H_5NO_2} \xrightarrow{\mathrm{Sn + HCl}} \mathrm{A} \xrightarrow{\mathrm{Br_2\ water}} \mathrm{B}$
OR
Q.12 (iv) (b)2 marks $How will you convert the following : (I) Benzoic acid to aniline (II) Aniline to p-bromoaniline$

Section A

2 marks each

Q.12 marks $\mathrm{CH_3CH_2CHO}$
Q.22 marks $Define molar conductivity for the solution of an electrolyte. How does it vary with concentration ?$
Q.32 marks $2\mathrm{N_2O_5\,(g)} \longrightarrow 4\mathrm{NO_2\,(g)} + \mathrm{O_2\,(g)}$

Section B

3 marks each

Q.43 marks $Account for the following : (i) Transition metals and their compounds show catalytic activities. (ii) Zn, Cd and Hg are non-transition elements. (iii) Zr and Hf are of almost identical atomic radii.$

Q.53 marks

\mathrm{E}^{\ominus}_{\mathrm{M^{2+}/M}}

Q.6 (a)3 marks $Write three differences between Lyophobic sol and Lyophilic sol.$
OR
Q.6 (b)3 marks $(i) Write the dispersed phase and dispersion medium of 'milk'. (ii) What is the cause of Brownian movement in colloidal particles ? (iii) Why does physisorption decrease with increase in temperature ?$
Q.7 (a)3 marks $Write the equations involved in the following reactions : (i) Cannizzaro reaction (ii) Aldol condensation (iii) Hell-Volhard-Zelinsky reaction$
OR
Q.7 (b)3 marks $\mathrm{F-CH_2-COOH}$
Q.83 marks $t_{1/2}$
Q.9 (a)3 marks $\mathrm{C_6H_5CHO} \xrightarrow[273-283\ \mathrm{K}]{\mathrm{HNO_3 + H_2SO_4}}$
OR
Q.9 (b)3 marks $(i) Oxidation of propanal is easier than propanone. Why ? (ii) How can you distinguish between Acetophenone and Benzophenone ? (iii) Draw the structure of the following derivative : 2,4-Dinitrophenylhydrazone of Propanone$
Q.103 marks $\mathrm{Zn\,(s)} \mid \mathrm{Zn^{2+}}\,(0{\cdot}01\ \mathrm{M}) \parallel (0{\cdot}001\ \mathrm{M})\ \mathrm{Ag^{+}} \mid \mathrm{Ag\,(s)}$
Q.11 (a)3 marks $\mathrm{[NiCl_4]^{2-}}$
OR
Q.11 (b)3 marks $\mathrm{[Co(NH_3)_4(H_2O)Cl]Cl_2}$

$\mathrm{E}^{\ominus}_{\mathrm{M^{2+}/M}}$	Cr	Mn	Fe	Co	Ni	Cu	Zn
	$-\,0{\cdot}91$	$-\,1{\cdot}18$	$-\,0{\cdot}44$	$-\,0{\cdot}28$	$-\,0{\cdot}25$	$+\,0{\cdot}34$	$-\,0{\cdot}76$

Section C

Amines constitute an important class of organic compounds derived by replacing one or more hydrogen atoms of ammonia molecule by alkyl/aryl groups. Amines are usually formed from nitro compounds, halides, amides, etc. They exhibit hydrogen bonding which influences their physical properties. Alkyl amines are found to be stronger bases than ammonia. In aromatic amines, electron releasing and withdrawing groups, respectively increase and decrease their basic character. Reactions of amines are governed by availability of the unshared pair of electrons on nitrogen. Influence of the number of hydrogen atoms at nitrogen atom on the type of reactions and nature of products is responsible for identification and distinction between primary, secondary and tertiary amines. Reactivity of aromatic amines can be controlled by acylation process.
Q.12 (i)1 mark $Why does aniline not give Friedel-Crafts reaction ?$
Q.12 (ii)1 mark $\mathrm{pK_b}$
Q.12 (iii)1 mark $\mathrm{CH_3CH_2NH_2}$
Q.12 (iv) (a)2 marks $\mathrm{C_6H_5NO_2} \xrightarrow{\mathrm{Sn + HCl}} \mathrm{A} \xrightarrow{\mathrm{Br_2\ water}} \mathrm{B}$
OR
Q.12 (iv) (b)2 marks $How will you convert the following : (I) Benzoic acid to aniline (II) Aniline to p-bromoaniline$

Section A

2 marks each

Q.12 marks $\mathrm{CH_3CHO}$
Q.22 marks $0{\cdot}001$
Q.32 marks $A reaction is first order in X and second order in Y. (i) How is the rate affected on increasing the concentration of Y three times ? (ii) How is the rate affected when the concentrations of both X and Y are doubled ?$

Section B

3 marks each

Q.4 (a)3 marks $\mathrm{CH_3MgBr} + \mathrm{CO_2} \xrightarrow{\mathrm{H_3O^+}}$
OR
Q.4 (b)3 marks $\mathrm{CH_3CHO}$
Q.5 (a)3 marks $\mathrm{C_6H_5CHO} \xrightarrow[273-283\ \mathrm{K}]{\mathrm{HNO_3 + H_2SO_4}}$
OR
Q.5 (b)3 marks $(i) Oxidation of propanal is easier than propanone. Why ? (ii) How can you distinguish between Acetophenone and Benzophenone ? (iii) Draw the structure of the following derivative : 2,4-Dinitrophenylhydrazone of Propanone$
Q.63 marks $\mathrm{Zn\,(s)} \mid \mathrm{Zn^{2+}}\,(0{\cdot}01\ \mathrm{M}) \parallel (0{\cdot}001\ \mathrm{M})\ \mathrm{Ag^{+}} \mid \mathrm{Ag\,(s)}$
Q.7 (a)3 marks $Write three differences between Lyophobic sol and Lyophilic sol.$
OR
Q.7 (b)3 marks $(i) Write the dispersed phase and dispersion medium of 'milk'. (ii) What is the cause of Brownian movement in colloidal particles ? (iii) Why does physisorption decrease with increase in temperature ?$
Q.83 marks $t_{1/2}$
Q.93 marks $Account for the following : (i) Transition metals and their compounds show catalytic activities. (ii) Zn, Cd and Hg are non-transition elements. (iii) Zr and Hf are of almost identical atomic radii.$
Q.10 (a)3 marks $\mathrm{[NiCl_4]^{2-}}$
OR
Q.10 (b)3 marks $\mathrm{[Co(NH_3)_4(H_2O)Cl]Cl_2}$

Q.113 marks

\mathrm{E}^{\ominus}_{\mathrm{M^{2+}/M}}

$\mathrm{E}^{\ominus}_{\mathrm{M^{2+}/M}}$	Cr	Mn	Fe	Co	Ni	Cu	Zn
	$-\,0{\cdot}91$	$-\,1{\cdot}18$	$-\,0{\cdot}44$	$-\,0{\cdot}28$	$-\,0{\cdot}25$	$+\,0{\cdot}34$	$-\,0{\cdot}76$

Section C

Amines constitute an important class of organic compounds derived by replacing one or more hydrogen atoms of ammonia molecule by alkyl/aryl groups. Amines are usually formed from nitro compounds, halides, amides, etc. They exhibit hydrogen bonding which influences their physical properties. Alkyl amines are found to be stronger bases than ammonia. In aromatic amines, electron releasing and withdrawing groups, respectively increase and decrease their basic character. Reactions of amines are governed by availability of the unshared pair of electrons on nitrogen. Influence of the number of hydrogen atoms at nitrogen atom on the type of reactions and nature of products is responsible for identification and distinction between primary, secondary and tertiary amines. Reactivity of aromatic amines can be controlled by acylation process.
Q.12 (i)1 mark $Why does aniline not give Friedel-Crafts reaction ?$
Q.12 (ii)1 mark $\mathrm{pK_b}$
Q.12 (iii)1 mark $\mathrm{CH_3CH_2NH_2}$
Q.12 (iv) (a)2 marks $\mathrm{C_6H_5NO_2} \xrightarrow{\mathrm{Sn + HCl}} \mathrm{A} \xrightarrow{\mathrm{Br_2\ water}} \mathrm{B}$
OR
Q.12 (iv) (b)2 marks $How will you convert the following : (I) Benzoic acid to aniline (II) Aniline to p-bromoaniline$