Science (English Medium) Class 11 - CBSE Question Bank Solutions for Chemistry

Give reasons: Ice floats on water.

\[\ce{H2O2}\] is a better oxidising agent than water. Explain.

Melting point, enthalpy of vapourisation and viscosity data of \[\ce{H2O}\] and \[\ce{D2O}\] is given below :

On the basis of this data explain in which of these liquids intermolecular forces are stronger?

Explain why \[\ce{HCl}\] is a gas and \[\ce{HF}\] is a liquid.

Why does water show high boiling point as compared to hydrogen sulphide? Give reasons for your answer.

How will you account for 104.5° bond angle in water?

Write two reactions to explain amphoteric nature of water.

Which of the following are the correct reasons for anomalous behaviour of lithium?

(i) Exceptionally small size of its atom.

(ii) Its high polarising power.

(iii) It has high degree of hydration.

(iv) Exceptionally low ionisation enthalpy.

Write the general outer electronic configuration of f- block elements.

An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol.

An ion with mass number 37 possesses one unit of negative charge. If the ion contains 11.1% more neutrons than the electrons, find the symbol of the ion.

An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons. Assign the symbol to this ion.

What is K_c for the following equilibrium when the equilibrium concentration of each substance is: [SO₂] = 0.60 M, [O₂] = 0.82 M and [SO₃] = 1.90 M?

\[\ce{2SO2(g) + O2(g) ⇌ 2SO3(g)}\]

Write the expression for the equilibrium constant, K_c for each of the following reactions:

\[\ce{2NOCl (g) ⇌ 2NO (g) + Cl2 (g)}\]

Write the expression for the equilibrium constant, Kc for the following reactions:

\[\ce{2Cu(NO3)2 (s) ⇌ 2CuO (s) + 4NO2 (g) + O2 (g)}\]

Write the expression for the equilibrium constant, K_c for the following reactions:

\[\ce{CH3COOC2H5(aq) + H2O(l) ⇌CH3COOH (aq) + C2H5OH (aq)}\]

Write the expression for the equilibrium constant, K_c for following reactions:

\[\ce{Fe^{3+}(aq) + 3OH^-(aq) ⇌ Fe(OH)3(s)}\]

Write the expression for the equilibrium constant, Kc for the following reactions

\[\ce{I2 (s) + 5F2 ⇌ 2IF5}\]

A reaction between N₂ and O₂ takes place as follows:

\[\ce{2N2 (g) + O2 (g) ⇌ 2N2O (g)}\]

If a mixture of 0.482 mol of N₂ and 0.933 mol of O₂ is placed in a 10 L reaction vessel and allowed to form N₂O at a temperature for which K_c = 2.0 × 10^-37, determine the composition of equilibrium mixture.

Nitric oxide reacts with Br₂ and gives nitrosyl bromide as per reaction given below:

\[\ce{2NO(g) + Br2 (g) ⇌ 2NOBr (g)}\]

When 0.087 mol of NO and 0.0437 mol of Br₂ are mixed in a closed container at the constant temperature, 0.0518 mol of NOBr is obtained at equilibrium. Calculate the equilibrium amount of NO and Br₂.