CBSE Class 12 Chemistry 2026 question paper (56/4)

1. A.
   Mustard gas
2. B.
   Tear gas
3. C.
   Chlorine gas
4. D.
   Phosgene gas

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1. A.
   2-methyl-1-propanol
2. B.
   Butan-2-ol
3. C.
   2-methyl-2-propanol
4. D.
   Butan-1-ol

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1. A.
   $\mathrm{d_{xy}}$, $\mathrm{d_{yz}}$, $\mathrm{d_{xz}}$
2. B.
   $\mathrm{d_{x^2-y^2}}$, $\mathrm{d_{z^2}}$
3. C.
   $\mathrm{d_{xy}}$, $\mathrm{d_{x^2-y^2}}$
4. D.
   $\mathrm{d_{xz}}$, $\mathrm{d_{z^2}}$

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1. A.
   Ethane-1,2-diamine
2. B.
   Oxalate ion
3. C.
   Dimethylglyoxime
4. D.
   EDTA

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1. A.
   one unpaired electron
2. B.
   two unpaired electrons
3. C.
   three unpaired electrons
4. D.
   fully paired electrons

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1. A.
   $\mathrm{(C_2H_5)_3N}$ > $\mathrm{(C_2H_5)_2NH}$ > $\mathrm{C_2H_5NH_2}$
2. B.
   $\mathrm{(C_2H_5)_2NH}$ > $\mathrm{C_2H_5NH_2}$ > $\mathrm{(C_2H_5)_3N}$
3. C.
   $\mathrm{C_2H_5NH_2}$ > $\mathrm{(C_2H_5)_2NH}$ > $\mathrm{(C_2H_5)_3N}$
4. D.
   $\mathrm{(C_2H_5)_2NH}$ > $\mathrm{(C_2H_5)_3N}$ > $\mathrm{C_2H_5NH_2}$

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1. A.
   $100{\cdot}52\ ^{\circ}\mathrm{C}$
2. B.
   $101{\cdot}04\ ^{\circ}\mathrm{C}$
3. C.
   $100{\cdot}04\ ^{\circ}\mathrm{C}$
4. D.
   $101{\cdot}52\ ^{\circ}\mathrm{C}$

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1. A.
   vapour pressure of the solution increases
2. B.
   heating occurs
3. C.
   cooling occurs
4. D.
   equilibrium remains unaffected

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1. A.
   By decreasing only the $\mathrm{[Mg^{2+}]}$ to $0{\cdot}1$ M
2. B.
   By decreasing only the $\mathrm{[Cu^{2+}]}$ to $0{\cdot}1$ M
3. C.
   By increasing both $\mathrm{[Mg^{2+}]}$ and $\mathrm{[Cu^{2+}]}$ to $2{\cdot}0$ M
4. D.
   By increasing only the $\mathrm{[Mg^{2+}]}$ to $2{\cdot}0$ M

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1. A.
   $5{\cdot}6 \times 10^{-3}$ $\mathrm{s^{-1}}$
2. B.
   $2{\cdot}8 \times 10^{-4}$ $\mathrm{s^{-1}}$
3. C.
   $2{\cdot}8 \times 10^{-5}$ $\mathrm{s^{-1}}$
4. D.
   $2{\cdot}8 \times 10^{-3}$ $\mathrm{s^{-1}}$

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1. A.
   amino acids
2. B.
   nucleosides
3. C.
   nucleotides
4. D.
   pentose sugar

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1. A.
   $\mathrm{HCO_3^{-}}$
2. B.
   $\mathrm{CO_3^{2-}}$
3. C.
   $\mathrm{CO_2}$
4. D.
   $\mathrm{CO}$

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   High ionization enthalpy
2. B.
   Similar atomic radii
3. C.
   Catalytic property
4. D.
   Complex formation

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1. A.
   $\mathrm{d_{x^2-y^2}}$, $\mathrm{d_{z^2}}$
2. B.
   $\mathrm{d_{x^2-y^2}}$, $\mathrm{d_{xy}}$
3. C.
   $\mathrm{d_{xy}}$, $\mathrm{d_{yz}}$, $\mathrm{d_{z^2}}$
4. D.
   $\mathrm{d_{xy}}$, $\mathrm{d_{yz}}$, $\mathrm{d_{xz}}$

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1. A.
   Vinylic
2. B.
   Allylic
3. C.
   Benzylic
4. D.
   Aryl

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1. A.
   Nucleophilic addition reaction
2. B.
   Electrophilic substitution reaction
3. C.
   Nucleophilic substitution reaction
4. D.
   Electrophilic addition reaction

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1. A.
   3
2. B.
   4
3. C.
   2
4. D.
   1

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1. A.
   $\mathrm{(CH_3)_3N}$ > $\mathrm{(CH_3)_2NH}$ > $\mathrm{CH_3 - NH_2}$
2. B.
   $\mathrm{CH_3 - NH_2}$ > $\mathrm{(CH_3)_2NH}$ > $\mathrm{(CH_3)_3N}$
3. C.
   $\mathrm{(CH_3)_2NH}$ > $\mathrm{CH_3 - NH_2}$ > $\mathrm{(CH_3)_3N}$
4. D.
   $\mathrm{(CH_3)_2NH}$ > $\mathrm{(CH_3)_3N}$ > $\mathrm{CH_3 - NH_2}$

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1. A.
   vapour pressure of the solution increases
2. B.
   heating occurs
3. C.
   cooling occurs
4. D.
   equilibrium remains unaffected

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1. A.
   $100{\cdot}52\ ^{\circ}\mathrm{C}$
2. B.
   $101{\cdot}04\ ^{\circ}\mathrm{C}$
3. C.
   $100{\cdot}04\ ^{\circ}\mathrm{C}$
4. D.
   $101{\cdot}52\ ^{\circ}\mathrm{C}$

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1. A.
   $5{\cdot}6 \times 10^{-3}$ $\mathrm{s^{-1}}$
2. B.
   $2{\cdot}8 \times 10^{-4}$ $\mathrm{s^{-1}}$
3. C.
   $2{\cdot}8 \times 10^{-5}$ $\mathrm{s^{-1}}$
4. D.
   $2{\cdot}8 \times 10^{-3}$ $\mathrm{s^{-1}}$

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1. A.
   By decreasing only the $\mathrm{[Mg^{2+}]}$ to $0{\cdot}1$ M
2. B.
   By decreasing only the $\mathrm{[Cu^{2+}]}$ to $0{\cdot}1$ M
3. C.
   By increasing both $\mathrm{[Mg^{2+}]}$ and $\mathrm{[Cu^{2+}]}$ to $2{\cdot}0$ M
4. D.
   By increasing only the $\mathrm{[Mg^{2+}]}$ to $2{\cdot}0$ M

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1. A.
   $\mathrm{H_2O}$
2. B.
   $\mathrm{LiAlH_4}$
3. C.
   $\mathrm{C_2H_5OH}$
4. D.
   $\mathrm{CuCN}$

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1. A.
   Vitamin K
2. B.
   Vitamin A
3. C.
   Vitamin B
4. D.
   Vitamin D

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Follows first order kinetics
2. B.
   Favoured by polar protic solvents
3. C.
   Proceeds through the formation of carbocation
4. D.
   Results in inversion of configuration

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1. A.
   Ketones
2. B.
   Alkenes
3. C.
   Aldehydes
4. D.
   Carboxylic acid

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1. A.
   4
2. B.
   3
3. C.
   6
4. D.
   2

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1. A.
   $\mathrm{d_{xy}}$, $\mathrm{d_{yz}}$, $\mathrm{d_{xz}}$
2. B.
   $\mathrm{d_{x^2-y^2}}$, $\mathrm{d_{z^2}}$
3. C.
   $\mathrm{d_{xy}}$, $\mathrm{d_{x^2-y^2}}$
4. D.
   $\mathrm{d_{xz}}$, $\mathrm{d_{z^2}}$

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1. A.
   Zn
2. B.
   Cu
3. C.
   Fe
4. D.
   Cr

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1. A.
   $100{\cdot}52\ ^{\circ}\mathrm{C}$
2. B.
   $101{\cdot}04\ ^{\circ}\mathrm{C}$
3. C.
   $100{\cdot}04\ ^{\circ}\mathrm{C}$
4. D.
   $101{\cdot}52\ ^{\circ}\mathrm{C}$

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1. A.
   $\mathrm{C_6H_5NH_2}$ > $\mathrm{C_6H_5NHCH_3}$ > $\mathrm{C_2H_5NH_2}$
2. B.
   $\mathrm{C_2H_5NH_2}$ > $\mathrm{C_6H_5NH_2}$ > $\mathrm{C_6H_5NHCH_3}$
3. C.
   $\mathrm{C_6H_5NH_2}$ > $\mathrm{C_2H_5NH_2}$ > $\mathrm{C_6H_5NHCH_3}$
4. D.
   $\mathrm{C_6H_5NHCH_3}$ > $\mathrm{C_6H_5NH_2}$ > $\mathrm{C_2H_5NH_2}$

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1. A.
   By decreasing only the $\mathrm{[Mg^{2+}]}$ to $0{\cdot}1$ M
2. B.
   By decreasing only the $\mathrm{[Cu^{2+}]}$ to $0{\cdot}1$ M
3. C.
   By increasing both $\mathrm{[Mg^{2+}]}$ and $\mathrm{[Cu^{2+}]}$ to $2{\cdot}0$ M
4. D.
   By increasing only the $\mathrm{[Mg^{2+}]}$ to $2{\cdot}0$ M

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1. A.
   vapour pressure of the solution increases
2. B.
   heating occurs
3. C.
   cooling occurs
4. D.
   equilibrium remains unaffected

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1. A.
   primary structure of proteins
2. B.
   secondary structure of proteins
3. C.
   tertiary structure of proteins
4. D.
   quaternary structure of proteins

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