CBSE Class 12 2025 Chemistry 56-7-2 Question Paper Set-2: Download Solutions with Answer Key

Among the following outermost electronic configurations of transition metals, which one shows the highest oxidation state?

• (A) \(3d^6\,4s^2\)
• (B) \(3d^5\,4s^1\)
• (C) \(3d^5\,4s^2\)
• (D) \(3d^3\,4s^2\)

Which of the following solution in water will have the lowest freezing point?

• (A) 1% KCl
• (B) 1% glucose
• (C) 1% urea
• (D) 1% CaCl\(_2\)

Kohlrausch gave the following relation for strong electrolytes:
\(\Lambda_m = \Lambda_m^0 - A\sqrt{C}\)

Which of the following equality holds true?

• (A) \(\Lambda_m = \Lambda_m^0\) as C \(\longrightarrow\) 1
• (B) \(\Lambda_m = \Lambda_m^0\) as C \(\longrightarrow\) 0
• (C) \(\Lambda_m = \Lambda_m^0\) as C \(\longrightarrow \infty\)
• (D) \(\Lambda_m = \Lambda_m^0\) as C \(\longrightarrow \sqrt{A}\)

Unit of rate constant ‘k’ for a second order reaction is:

• (A) s\(^{-1}\)
• (B) mol L\(^{-1}\) s\(^{-1}\)
• (C) mol\(^{-1}\) L s\(^{-1}\)
• (D) mol\(^{-2}\) L s\(^{-1}\)

Which of the following represents the fraction of molecules with energies equal to or greater than E\(_a\)?

• (A) \(-\frac{E_a}{RT}\)
• (B) \(\frac{E_a}{RT}\)
• (C) \(e^{-E_a/RT}\)
• (D) \(+\frac{E_a}{RT}\)

The number of moles of AgCl precipitated when excess AgNO\(_3\) solution is mixed with one mole of [Co(NH\(_3\))\(_4\)Cl\(_2\)]Cl is:

• (A) 1
• (B) 0
• (C) 2
• (D) 3

The synthesis of alkyl fluoride is best carried out by:

• (A) Finkelstein reaction
• (B) Swarts reaction
• (C) Sandmeyer reaction
• (D) Wurtz reaction

In the reaction R–OH + HCl \(\xrightarrow{ZnCl_2}\) RCl + H\(_2\)O, what is the correct order of reactivity of alcohols?

• (A) 1\(^\circ\) \(<\) 2\(^\circ\) \(<\) 3\(^\circ\)
• (B) 2\(^\circ\) \(<\) 1\(^\circ\) \(<\) 3\(^\circ\)
• (C) 3\(^\circ\) \(>\) 1\(^\circ\) \(<\) 2\(^\circ\)
• (D) 1\(^\circ\) \(>\) 2\(^\circ\) \(>\) 3\(^\circ\)

Phenol reacts with Bromine (Br\(_2\)) water to form:

• (A) 2,4-dibromophenol
• (B) 2-bromophenol
• (C) 2,4,6-tribromophenol
• (D) 4-bromophenol

When excess of alkyl iodide is treated with ammonia, the product obtained is:

• (A) Primary amine
• (B) Secondary amine
• (C) Tertiary amine
• (D) A mixture of amines

An amine ‘X’ reacts with Hinsberg reagent and the product obtained is insoluble in alkali. The amine ‘X’ is:

• (A) (CH\(_3\))\(_2\)–NH
• (B) (CH\(_3\))\(_3\)N
• (C) CH\(_3\)–CH\(_2\)–NH\(_2\)
• (D) \chemfig{*6(=-=-=-)-NH_2} (Aniline)

‘Scurvy’ is caused due to the deficiency of:

• (A) Vitamin A
• (B) Vitamin B\(_2\)
• (C) Vitamin C
• (D) Vitamin D
• (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• (C) Assertion (A) is true, but Reason (R) is false.

Reason (R): o-nitrophenol is steam volatile due to intramolecular hydrogen bonding.

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

Reason (R): Boiling point of water inside the pressure cooker is lowered down.

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

Reason (R): This is due to varying stability of f\(^0\), f\(^7\) and f\(^{14}\) configurations.

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

Reason (R): One of the two glucose units can open to expose free aldehydic group in solution.

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

What is meant by negative deviation from Raoult’s law? Give an example. What type of azeotrope is formed by negative deviation?

Write the IUPAC name of the complex [Pt(en)\(_2\)Cl\(_2\)]\(^{2+}\). Draw the structure of geometrical isomer of this complex which is optically inactive.

Write the formula of the following coordination compound: Pentaamminecarbonatocobalt(III) chloride

Write the IUPAC name of the linkage isomer of the complex [Co(NH\(_3\))\(_5\)(NO\(_2\))]Cl\(_2\).

State a condition under which a bimolecular reaction is kinetically first order reaction. Give an example. For which type of reactions, do order and molecularity have the same value?

Write two differences between Amylose and Amylopectin components of starch.

Why are haloarenes less reactive towards nucleophilic substitution reaction? How does the presence of nitro (–NO\(_2\)) group at ortho- and para-positions in haloarenes increase the reactivity towards nucleophilic substitution reaction?

(a) Essential amino acids and Non-essential amino acids

Peptide linkage and Glycosidic linkage

Fibrous protein and Globular protein

Give reasons for the following:


% (a) Benzoic acid and Friedel-Crafts
(a) Benzoic acid does not undergo Friedel-Crafts reaction.

HCHO is more reactive than CH\(_3\)CHO towards addition of HCN.

Vinyl group directly attached with carboxylic acid should decrease acidity due to resonance, but it increases acidity. Explain.

Write structure of the products of the following reactions:






% (a) Anisole + HI
(a) Anisole (\chemfig{*6(-=-(-OCH_3)=-=)) + HI → ?

Phenol + conc. HNO\(_3\) → ?

Cyclohexylmagnesium bromide + HCHO \(\xrightarrow{H^+/H_2O}\) → ?

First order decomposition of N\(_2\)O\(_5\) (g) at constant volume:


2N\(_2\)O\(_5\) (g) → 2N\(_2\)O\(_4\) (g) + O\(_2\) (g)


\begin{tabular{|c|c|
\hline
Time (s) & Total Pressure (atm)

\hline
0 & 0.50

\hline
100 & 0.625

\hline
\end{tabular


Calculate rate constant.

A compound (A) with molecular formula C\(_4\)H\(_9\)I which is a primary alkyl halide, reacts with alcoholic KOH to give compound (B). Compound (B) reacts with HI to give (C) which is an isomer of (A). When (A) reacts with Na metal in dry ether, it gives compound (D), C\(_8\)H\(_{18}\), which is different from the compound formed when n-butyl iodide reacts with sodium. Write the structures of (A), (B), (C) and (D). Write the chemical equation when compound (A) is reacted with alcoholic KOH.

(a) Write the name of the cell which is generally used in inverters. Write the reactions taking place at anode and cathode of this cell, when it is in use.

Explain why electrolysis of an aqueous solution of NaCl gives H\(_2\) gas at cathode and Cl\(_2\) gas at anode? Write overall reaction.


Given: E\(^\circ\)\(_{Na^+/Na}\) = –2.71 V, E\(^\circ\)\(_{H_2O/H_2}\) = –0.83 V, E\(^\circ\)\(_{Cl_2/Cl^-}\) = +1.36 V, E\(^\circ\)\(_{H_2O/O_2}\) = +1.23 V.

0.3 g of acetic acid (M = 60 g mol\(^{-1}\)) dissolved in 30 g benzene shows a depression in freezing point equal to 0.45\(^\circ\)C. Calculate the percentage association of acetic acid if it forms a dimer in solution. (Given: K\(_f\) for benzene = 5.12 K kg mol\(^{-1}\))

How can you convert ethanoic acid to methanamine?

How can you convert propanenitrile to 1-aminopropane?

Why is pK\(_b\) value of aniline more than that of methylamine?

Arrange the following in increasing order of basic strength in aqueous solution:

CH\(_3\)–NH\(_2\), (CH\(_3\))\(_2\)NH, (CH\(_3\))\(_3\)N

Give the structures of A and B in the following reaction:

C\(_6\)H\(_5\)NO\(_2\) \(\xrightarrow{Fe/HCl}\) A \(\xrightarrow{HNO_2,\,273\,K}\) B

On the basis of CFT, explain why [Ti(H\(_2\)O)\(_6\)]Cl\(_3\) complex is coloured? What happens on heating the complex [Ti(H\(_2\)O)\(_6\)]Cl\(_3\)? Give reason. [Atomic no. : Ti = 22]

What is crystal field splitting energy?

On the basis of \(\Delta_0\) and P (pairing energy), how can you differentiate between a strong field ligand and a weak field ligand?

Why are low spin tetrahedral complexes rarely observed?

Calculate the emf of the following cell at 25\(^\circ\)C :

Zn(s) \(\mid\) Zn\(^{2+}\) (0.1 M) \(\parallel\) H\(^+\) (0.01 M) \(\mid\) H\(_2\)(g) (1 bar), Pt(s)


Given: E\(^\circ_{Zn^{2+}/Zn}\) = –0.76 V, E\(^\circ_{2H^+/H_2}\) = 0.00 V, log 10 = 1

State Faraday’s second law of electrolysis. How much electricity is required in terms of Faraday for the reduction of 1 mol of Cr\(_2\)O\(_7^{2-}\) to Cr\(^{3+}\) ?

The conductivity of 0.20 M solution of KCl is 2.48 × 10\(^{-2}\) S cm\(^{-1}\). Calculate its molar conductivity and degree of dissociation (\(\alpha\)).


Given: \(\lambda^\circ_{K^+}\) = 73.5 S cm\(^2\) mol\(^{-1}\), \(\lambda^\circ_{Cl^-}\) = 76.5 S cm\(^2\) mol\(^{-1}\)

Calculate \(\Delta_r G^\circ\) of the following cell:

Mg(s) + Cu\(^{2+}\)(aq) \(\longrightarrow\) Mg\(^{2+}\)(aq) + Cu(s)


Given: E\(^\circ_{Mg^{2+}/Mg}\) = –2.37 V, E\(^\circ_{Cu^{2+}/Cu}\) = +0.34 V,

1 F = 96500 C mol\(^{-1}\)

What type of cell is mercury cell? Why is it more advantageous than dry cell?

Account for the following :


(I) The E\(^\circ_{Mn^{2+}/Mn}\) value for manganese is highly negative, whereas E\(^\circ_{Mn^{3+}/Mn^{2+}}\) is highly positive.

Complete the following ionic equations :


(I) 5SO\(_3^{2-}\) + 2MnO\(_4^-\) + 6H\(^+\) ⟶ ?

Answer the following questions :


(i) Name two elements of 3d series for which the third ionisation enthalpies are quite high.

An organic compound (X) having molecular formula C\(_5\)H\(_{10}\)O can show various properties depending on its structures. Draw each of the structures if it :


(I) shows Cannizzaro reaction.

Write the reaction involved in the following :


(I) Clemmensen reduction

Draw structure of the methyl hemiacetal of methanal.

There are two –NH\(_2\) groups in semicarbazide. However only one is involved in the formation of semicarbazones. Give reason.

How will you convert ethanol to 3-hydroxybutanal?

Complete the following equation:

OH \(\xrightarrow{CrO_3}\) ?

Write the final product formed when phthalic acid is treated with NH\(_3\) followed by strong heating.