CBSE Class 12 Chemistry 2026 question paper (56/2)

Maximum marks 70 · Time 3 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

1 mark each

Q.11 mark $\mathrm{Zn_{(s)}} + \mathrm{Ag_2O_{(s)}} + \mathrm{H_2O}(l) \rightarrow \mathrm{Zn^{2+}_{(aq)}} + 2\mathrm{Ag_{(s)}} + 2\mathrm{OH^{-}_{(aq)}}$
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Q.21 mark $Identify the correct statement :$
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Q.31 mark $\mathrm{A} + 2\mathrm{B} \rightarrow$
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Q.41 mark $Electronic configuration of chromium is :$
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Q.51 mark $\mathrm{[Pt(NH_3)_2Cl_2]}$
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Q.61 mark $Which of the following is heteroleptic complex ?$
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Q.71 mark $Which of the following molecules is chiral in nature ?$
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Q.81 mark $Identify the correct increasing order of boiling points of the given compounds :$
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Q.91 mark $Identify the compound produced by the reduction of Ethanenitrile with Lithium aluminium hydride :$
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Q.101 mark $The base which is present in DNA but not in RNA is :$
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Q.111 mark $\alpha$
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Q.121 mark $Which of the following reactions is not explained by the open chain structure of glucose ?$
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For question number 13 to 16, two statements are given – one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below :
Q.131 mark $2\mathrm{HI} \longrightarrow \mathrm{H_2} + \mathrm{I_2}$
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Q.141 mark $Assertion (A) : Zinc, cadmium and mercury are not considered as transition elements. Reason (R) : These elements have completely filled orbitals in their ground state as well as in their common oxidation states.$
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Q.151 mark $Assertion (A) : Aromatic primary amines can be prepared by Gabriel Phthalimide synthesis. Reason (R) : Aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.$
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Q.161 mark $Assertion (A) : Glucose gets oxidized to six carbon gluconic acid on reaction with bromine water. Reason (R) : The carbonyl group is absent in the open chain structure of glucose.$
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Section B

2 marks each

Q.17 (A)2 marks $\mathrm{L^{-1}}$
OR
Q.17 (B)2 marks $2.54 \times 10^{-3}$
Q.182 marks $(a) Define activation energy. (b) Write the unit of rate constant for (i) zero order reaction, (ii) second order reaction.$
Q.192 marks $(a) First ionization enthalpy of Cr is lower than that of Zn. Why ? (b) Mention any one property of the transition elements which makes them good catalysts.$
Q.202 marks $\mathrm{[Co(en)_3]Cl_3}$
Q.212 marks $(a) Draw the structure of the given compound : 4-Bromo-3-methylpent-2-ene (b) What happens when chloroethane is treated with aqueous potassium hydroxide ?$

Section C

3 marks each

Q.223 marks $\mathrm{K_b}$
Q.233 marks $\mathrm{Sn} \mid \mathrm{Sn^{2+}}\ (0.001\ \mathrm{M}) \parallel \mathrm{H^{+}}\ (0.01\ \mathrm{M}) \mid \mathrm{H_{2(g)}}\ (1\ \mathrm{bar}) \mid \mathrm{Pt_{(s)}}$
Q.243 marks $2\mathrm{KMnO_4} \xrightarrow{513\ \mathrm{K}}$
Q.253 marks $\mathrm{[Co(NH_3)_6]^{3+}}$
Q.263 marks $+\ \mathrm{Br_2} \xrightarrow{\text{heat}}$
Q.273 marks $Write the reaction involved in (a) Rosenmund's reduction (b) Cannizzaro's reaction (c) Hell-Volhard-Zelinsky reaction$
Q.28 (A)3 marks $Define the following term : (a) Reducing sugar (b) Differentiate between the following : (i) Fibrous proteins and globular proteins (ii) Nucleotide and nucleoside$
OR
Q.28 (B)3 marks $\mathrm{H_2N-OH}$

Section D

Osmosis is a process by which the molecules of a solvent pass from a solution of low solute concentration to a solution of high solute concentration through a semi-permeable membrane. Osmotic pressure is a colligative property. When the applied pressure on a solution exceeds its osmotic pressure, reverse osmosis occurs. When two solutions are separated by a semipermeable membrane and they have same osmotic pressure they are said to be isotonic. Of the two solutions separated by a semipermeable membrane, if one is a lower osmotic pressure, it is said to be hypotonic relative to the second solution. If it has a higher osmotic pressure, than the second solution, it is said to be hypertonic relative to the second solution. The osmotic pressure associated with the fluid inside the blood cell is equivalent to that of 0.9% (mass/volume) sodium chloride solution called normal saline solution and it is safe to inject intravenously. Osmotic pressure is vital in daily life and nature. It helps in explain, why IV fluids match blood's osmotic pressure, its also the principle behind food preservation using salt or sugar.
Q.29 (a)2 marks $\mathrm{CaCl_2}$
Q.29 (b)1 mark $When raisins are kept in water, they get swollen. Name the phenomenon involved in this process.$
OR
Q.29 (b) OR1 mark $Why osmotic pressure is more advantageous than other colligative properties ?$
Q.29 (c)1 mark $Which phenomenon is responsible for desalination of sea water ?$
Like $\mathrm{NH_3}$ , nitrogen atom of amine is trivalent and carries an unshared pair of electrons. Nitrogen orbitals in amines are therefore $\mathrm{sp^3}$ hybridised and the geometry of amines is pyramidal. Lower aliphatic amines are soluble in water due to the formation of hydrogen bond with water molecules. The solubility decreases as the molar mass of amines increases due to increase in size of hydrophobic part. Higher amines are insoluble in water. However amines are less soluble in water than alcohols because of low electronegativity of nitrogen as compared to oxygen. Boiling points of isomeric amines follow the order $1^{\mathrm{o}} > 2^{\mathrm{o}} > 3^{\mathrm{o}}$ . It is due to the fact the amines are held together due to hydrogen bonding. Extent of hydrogen bonding is more in primary amines than in secondary amines as two hydrogen atoms are available for hydrogen bond formation. Tertiary amines do not show hydrogen bonding because of the absence of hydrogen atom attached to nitrogen. Amines can be prepared from, nitro compounds, nitriles, amides etc.
Q.30 (a)2 marks $\mathrm{CH_3CONH_2} \xrightarrow[\mathrm{(ii)\ H_2O}]{\mathrm{(i)\ LiAlH_4}}$
Q.30 (b)1 mark $Why primary amines have higher boiling points than tertiary amines ?$
Q.30 (c)1 mark $\mathrm{C_{10}H_7 - N(CH_3)_2}$
OR
Q.30 (c) OR1 mark $Out of Butan-1-amine and Butan-1-ol, which is more soluble in water ?$

Section E

5 marks each

Q.31 (A)5 marks $\mathrm{(CH_3)_2C=O}$
OR
Q.31 (B)5 marks $\mathrm{CH_2FCOOH}$
Q.32 (A)5 marks $\mathrm{L^{-1}}$
OR
Q.32 (B)5 marks $\Omega$
Q.33 (A)5 marks $\mathrm{C_2H_6O}$
OR
Q.33 (B)5 marks $(a) Write the reagents which are used in the given conversions : (i) Phenol to 2, 4, 6 - tribromophenol (ii) Propene to propan-1-ol (iii) Butan-2-one to butan-2-ol (b) Explain the mechanism of acid catalyzed hydration of alkene to form corresponding alcohol.$

Section A

1 mark each

Q.11 mark $Which of the following reactions is not explained by the open chain structure of glucose ?$
Tap an option to check your answer.
Q.21 mark $\alpha$
Tap an option to check your answer.
Q.31 mark $The base which is present in DNA but not in RNA is :$
Tap an option to check your answer.
Q.41 mark $Identify the compound produced by the reduction of Ethanenitrile with Lithium aluminium hydride :$
Tap an option to check your answer.
Q.51 mark $Identify the correct increasing order of boiling points of the given compounds :$
Tap an option to check your answer.
Q.61 mark $Which of the following molecules is chiral in nature ?$
Tap an option to check your answer.
Q.71 mark $Which of the following is heteroleptic complex ?$
Tap an option to check your answer.
Q.81 mark $\mathrm{[Pt(NH_3)_2Cl_2]}$
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Q.91 mark $Electronic configuration of chromium is :$
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Q.101 mark $\mathrm{A} + 2\mathrm{B} \rightarrow$
Tap an option to check your answer.
Q.111 mark $Identify the correct statement :$
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Q.121 mark $\mathrm{Zn_{(s)}} + \mathrm{Ag_2O_{(s)}} + \mathrm{H_2O}(l) \rightarrow \mathrm{Zn^{2+}_{(aq)}} + 2\mathrm{Ag_{(s)}} + 2\mathrm{OH^{-}_{(aq)}}$
Tap an option to check your answer.
For question number 13 to 16, two statements are given – one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below :
Q.131 mark $Assertion (A) : Glucose gets oxidized to six carbon gluconic acid on reaction with bromine water. Reason (R) : The carbonyl group is absent in the open chain structure of glucose.$
Tap an option to check your answer.
Q.141 mark $Assertion (A) : Aromatic primary amines can be prepared by Gabriel Phthalimide synthesis. Reason (R) : Aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.$
Tap an option to check your answer.
Q.151 mark $Assertion (A) : Zinc, cadmium and mercury are not considered as transition elements. Reason (R) : These elements have completely filled orbitals in their ground state as well as in their common oxidation states.$
Tap an option to check your answer.
Q.161 mark $2\mathrm{HI} \longrightarrow \mathrm{H_2} + \mathrm{I_2}$
Tap an option to check your answer.

Section B

2 marks each

Q.172 marks $(a) Draw the structure of the given compound : 4-Bromo-3-methylpent-2-ene (b) What happens when chloroethane is treated with aqueous potassium hydroxide ?$
Q.182 marks $(a) Define Collision frequency. (b) Write the units of (i) first order reaction and (ii) zero order reaction$
Q.192 marks $(a) Why is third ionization enthalpy of manganese very high ? (b) Why Zn, Cd and Hg are not regarded as transition elements ?$
Q.202 marks $\mathrm{[Pt(NH_3)(H_2O)Cl_2]}$
Q.21 (A)2 marks $\mathrm{L^{-1}}$
OR
Q.21 (B)2 marks $2.54 \times 10^{-3}$

Section C

3 marks each

Q.223 marks $\mathrm{K_b}$
Q.233 marks $\mathrm{Sn} \mid \mathrm{Sn^{2+}}\ (0.001\ \mathrm{M}) \parallel \mathrm{H^{+}}\ (0.01\ \mathrm{M}) \mid \mathrm{H_{2(g)}}\ (1\ \mathrm{bar}) \mid \mathrm{Pt_{(s)}}$
Q.243 marks $4\mathrm{FeCr_2O_4} + 8\mathrm{Na_2CO_3} + 7\mathrm{O_2} \longrightarrow$
Q.253 marks $\mathrm{[Fe(H_2O)_6]^{2+}}$
Q.263 marks $+\ \mathrm{Br_2} \xrightarrow{\text{heat}}$
Q.273 marks $Write the reaction involved in (a) Rosenmund's reduction (b) Cannizzaro's reaction (c) Hell-Volhard-Zelinsky reaction$
Q.28 (A)3 marks $(a) Define the following terms : (i) Denaturation as related to proteins (ii) Oligosaccharides (b) On the basis of structure differentiate between Amylose and Amylopectin.$
OR
Q.28 (B)3 marks $(a) What products would be formed when a nucleotide from DNA containing thymine is hydrolysed ? (b) How will you explain the presence of five -OH groups in glucose molecule which are attached to different carbon atoms ? (c) Write the reaction of glucose with HCN.$

Section D

Like $\mathrm{NH_3}$ , nitrogen atom of amine is trivalent and carries an unshared pair of electrons. Nitrogen orbitals in amines are therefore $\mathrm{sp^3}$ hybridised and the geometry of amines is pyramidal. Lower aliphatic amines are soluble in water due to the formation of hydrogen bond with water molecules. The solubility decreases as the molar mass of amines increases due to increase in size of hydrophobic part. Higher amines are insoluble in water. However amines are less soluble in water than alcohols because of low electronegativity of nitrogen as compared to oxygen. Boiling points of isomeric amines follow the order $1^{\mathrm{o}} > 2^{\mathrm{o}} > 3^{\mathrm{o}}$ . It is due to the fact the amines are held together due to hydrogen bonding. Extent of hydrogen bonding is more in primary amines than in secondary amines as two hydrogen atoms are available for hydrogen bond formation. Tertiary amines do not show hydrogen bonding because of the absence of hydrogen atom attached to nitrogen. Amines can be prepared from, nitro compounds, nitriles, amides etc.
Q.29 (a)2 marks $\mathrm{CH_3CONH_2} \xrightarrow[\mathrm{(ii)\ H_2O}]{\mathrm{(i)\ LiAlH_4}}$
Q.29 (b)1 mark $Why primary amines have higher boiling points than tertiary amines ?$
Q.29 (c)1 mark $\mathrm{C_{10}H_7 - N(CH_3)_2}$
OR
Q.29 (c) OR1 mark $Out of Butan-1-amine and Butan-1-ol, which is more soluble in water ?$
Osmosis is a process by which the molecules of a solvent pass from a solution of low solute concentration to a solution of high solute concentration through a semi-permeable membrane. Osmotic pressure is a colligative property. When the applied pressure on a solution exceeds its osmotic pressure, reverse osmosis occurs. When two solutions are separated by a semipermeable membrane and they have same osmotic pressure they are said to be isotonic. Of the two solutions separated by a semipermeable membrane, if one is a lower osmotic pressure, it is said to be hypotonic relative to the second solution. If it has a higher osmotic pressure, than the second solution, it is said to be hypertonic relative to the second solution. The osmotic pressure associated with the fluid inside the blood cell is equivalent to that of 0.9% (mass/volume) sodium chloride solution called normal saline solution and it is safe to inject intravenously. Osmotic pressure is vital in daily life and nature. It helps in explain, why IV fluids match blood's osmotic pressure, its also the principle behind food preservation using salt or sugar.
Q.30 (a)2 marks $\mathrm{CaCl_2}$
Q.30 (b)1 mark $When raisins are kept in water, they get swollen. Name the phenomenon involved in this process.$
OR
Q.30 (b) OR1 mark $Why osmotic pressure is more advantageous than other colligative properties ?$
Q.30 (c)1 mark $Which phenomenon is responsible for desalination of sea water ?$

Section E

5 marks each

Q.31 (A)5 marks $\mathrm{C_2H_6O}$
OR
Q.31 (B)5 marks $(a) Write the reagents which are used in the given conversions : (i) Phenol to 2, 4, 6 - tribromophenol (ii) Propene to propan-1-ol (iii) Butan-2-one to butan-2-ol (b) Explain the mechanism of acid catalyzed hydration of alkene to form corresponding alcohol.$
Q.32 (A)5 marks $\mathrm{(CH_3)_2C=O}$
OR
Q.32 (B)5 marks $\mathrm{CH_2FCOOH}$
Q.33 (A)5 marks $\mathrm{L^{-1}}$
OR
Q.33 (B)5 marks $\Omega$

Section A

1 mark each

Q.11 mark $Identify the correct statement :$
Tap an option to check your answer.
Q.21 mark $\mathrm{Zn_{(s)}} + \mathrm{Ag_2O_{(s)}} + \mathrm{H_2O}(l) \rightarrow \mathrm{Zn^{2+}_{(aq)}} + 2\mathrm{Ag_{(s)}} + 2\mathrm{OH^{-}_{(aq)}}$
Tap an option to check your answer.
Q.31 mark $Electronic configuration of chromium is :$
Tap an option to check your answer.
Q.41 mark $\mathrm{A} + 2\mathrm{B} \rightarrow$
Tap an option to check your answer.
Q.51 mark $Which of the following is heteroleptic complex ?$
Tap an option to check your answer.
Q.61 mark $\mathrm{[Pt(NH_3)_2Cl_2]}$
Tap an option to check your answer.
Q.71 mark $Identify the correct increasing order of boiling points of the given compounds :$
Tap an option to check your answer.
Q.81 mark $Which of the following molecules is chiral in nature ?$
Tap an option to check your answer.
Q.91 mark $The base which is present in DNA but not in RNA is :$
Tap an option to check your answer.
Q.101 mark $Identify the compound produced by the reduction of Ethanenitrile with Lithium aluminium hydride :$
Tap an option to check your answer.
Q.111 mark $Which of the following reactions is not explained by the open chain structure of glucose ?$
Tap an option to check your answer.
Q.121 mark $\alpha$
Tap an option to check your answer.
For question number 13 to 16, two statements are given – one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below :
Q.131 mark $Assertion (A) : Zinc, cadmium and mercury are not considered as transition elements. Reason (R) : These elements have completely filled orbitals in their ground state as well as in their common oxidation states.$
Tap an option to check your answer.
Q.141 mark $2\mathrm{HI} \longrightarrow \mathrm{H_2} + \mathrm{I_2}$
Tap an option to check your answer.
Q.151 mark $Assertion (A) : Glucose gets oxidized to six carbon gluconic acid on reaction with bromine water. Reason (R) : The carbonyl group is absent in the open chain structure of glucose.$
Tap an option to check your answer.
Q.161 mark $Assertion (A) : Aromatic primary amines can be prepared by Gabriel Phthalimide synthesis. Reason (R) : Aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.$
Tap an option to check your answer.

Section B

2 marks each

Q.172 marks $\mathrm{[Co(en)_3]Cl_3}$
Q.182 marks $(a) Define Effective collision. (b) Write the unit of (i) second order reaction and (ii) zero order reaction$
Q.192 marks $(a) Why second ionization enthalpies of chromium and copper are exceptionally higher than those of their neighbouring elements ? (b) Why transition elements form interstitial compounds ?$
Q.20 (A)2 marks $\mathrm{L^{-1}}$
OR
Q.20 (B)2 marks $2.54 \times 10^{-3}$
Q.212 marks $+\ \mathrm{CH_3-Cl} \xrightarrow[\text{dry ether}]{\mathrm{Na}}$

Section C

3 marks each

Q.223 marks $\mathrm{mol^{-1}}$
Q.233 marks $\mathrm{Sn} \mid \mathrm{Sn^{2+}}\ (0.001\ \mathrm{M}) \parallel \mathrm{H^{+}}\ (0.01\ \mathrm{M}) \mid \mathrm{H_{2(g)}}\ (1\ \mathrm{bar}) \mid \mathrm{Pt_{(s)}}$
Q.243 marks $2\mathrm{Na_2CrO_4} + 2\mathrm{H^{+}} \longrightarrow$
Q.253 marks $\mathrm{[Fe(H_2O)_6]^{3+}}$
Q.263 marks $\mathrm{CH_3CH(CH_3)CH(Br)CH_3}$
Q.273 marks $Write the reaction involved in (a) Rosenmund's reduction (b) Cannizzaro's reaction (c) Hell-Volhard-Zelinsky reaction$
Q.28 (A)3 marks $(a) Define the following terms : (i) Invert Sugar (ii) Polysaccharides (b) On the basis of structure differentiate between fibrous and globular proteins.$
OR
Q.28 (B)3 marks $(a) Why is glycogen known as animal starch ? (b) Differentiate between essential amino acids and non-essential amino acids. (c) What is the effect of denaturation on the structure of proteins ?$

Section D

Osmosis is a process by which the molecules of a solvent pass from a solution of low solute concentration to a solution of high solute concentration through a semi-permeable membrane. Osmotic pressure is a colligative property. When the applied pressure on a solution exceeds its osmotic pressure, reverse osmosis occurs. When two solutions are separated by a semipermeable membrane and they have same osmotic pressure they are said to be isotonic. Of the two solutions separated by a semipermeable membrane, if one is a lower osmotic pressure, it is said to be hypotonic relative to the second solution. If it has a higher osmotic pressure, than the second solution, it is said to be hypertonic relative to the second solution. The osmotic pressure associated with the fluid inside the blood cell is equivalent to that of 0.9% (mass/volume) sodium chloride solution called normal saline solution and it is safe to inject intravenously. Osmotic pressure is vital in daily life and nature. It helps in explain, why IV fluids match blood's osmotic pressure, its also the principle behind food preservation using salt or sugar.
Q.29 (a)2 marks $\mathrm{CaCl_2}$
Q.29 (b)1 mark $When raisins are kept in water, they get swollen. Name the phenomenon involved in this process.$
OR
Q.29 (b) OR1 mark $Why osmotic pressure is more advantageous than other colligative properties ?$
Q.29 (c)1 mark $Which phenomenon is responsible for desalination of sea water ?$
Like $\mathrm{NH_3}$ , nitrogen atom of amine is trivalent and carries an unshared pair of electrons. Nitrogen orbitals in amines are therefore $\mathrm{sp^3}$ hybridised and the geometry of amines is pyramidal. Lower aliphatic amines are soluble in water due to the formation of hydrogen bond with water molecules. The solubility decreases as the molar mass of amines increases due to increase in size of hydrophobic part. Higher amines are insoluble in water. However amines are less soluble in water than alcohols because of low electronegativity of nitrogen as compared to oxygen. Boiling points of isomeric amines follow the order $1^{\mathrm{o}} > 2^{\mathrm{o}} > 3^{\mathrm{o}}$ . It is due to the fact the amines are held together due to hydrogen bonding. Extent of hydrogen bonding is more in primary amines than in secondary amines as two hydrogen atoms are available for hydrogen bond formation. Tertiary amines do not show hydrogen bonding because of the absence of hydrogen atom attached to nitrogen. Amines can be prepared from, nitro compounds, nitriles, amides etc.
Q.30 (a)2 marks $\mathrm{CH_3CONH_2} \xrightarrow[\mathrm{(ii)\ H_2O}]{\mathrm{(i)\ LiAlH_4}}$
Q.30 (b)1 mark $Why primary amines have higher boiling points than tertiary amines ?$
Q.30 (c)1 mark $\mathrm{C_{10}H_7 - N(CH_3)_2}$
OR
Q.30 (c) OR1 mark $Out of Butan-1-amine and Butan-1-ol, which is more soluble in water ?$

Section E

5 marks each

Q.31 (A)5 marks $\mathrm{L^{-1}}$
OR
Q.31 (B)5 marks $\Omega$
Q.32 (A)5 marks $\mathrm{C_2H_6O}$
OR
Q.32 (B)5 marks $(a) Write the reagents which are used in the given conversions : (i) Phenol to 2, 4, 6 - tribromophenol (ii) Propene to propan-1-ol (iii) Butan-2-one to butan-2-ol (b) Explain the mechanism of acid catalyzed hydration of alkene to form corresponding alcohol.$
Q.33 (A)5 marks $\mathrm{(CH_3)_2C=O}$
OR
Q.33 (B)5 marks $\mathrm{CH_2FCOOH}$