11.

A metal crystallises in a face centred cubic structure. If the edge length of its unit cell is'a', the closest approach between two atoms in metallic crystal will be

• 2a

• 
• 
• 

Two reactions R₁ and R₂ have identical pre-exponential factors. Activation energy of R₁ exceeds that of R₂ by 10 kJ mol^–1. If k₁ and k₂ are rate constants for reactions R₁ and R₂ respectively at 300 K, then ln(k₂/k₁) is equal to-
(R = 8.314 J mol^–1K^–1)

• 8

• 12

• 6

• 6

The Tyndall effect is observed only when following conditions are satisfied:-
(a) The diameter of the dispersed particles is much smaller than the wavelength of the light used.
(b) The diameter of the dispersed particle is not much smaller than the wavelength of the light used.
(c) The refractive indices of the dispersed phase and dispersion medium are almost similar in magnitude.
(d) The refractive indices of the dispersed phase and dispersion medium differ greatly in magnitude.

• (a) and (d)

• (b) and (d)

• (a) and (c)

• (a) and (c)

Which of the following reactions is an example of a redox reaction?

• XeF₄ + O₂F₂ → XeF₆ + O₂

• XeF₂ + PF₅ → [XeF]+PF₆^–

• XeF₆ + H₂O → XeOF₄ + 2HF

• XeF₆ + H₂O → XeOF₄ + 2HF

The products obtained when chlorine gas reacts with cold and dilute aqueous NaOH are

• ClO^– and ClO₃^–

• ClO₂^- and ClO₃^-

• Cl^– and ClO^–

• Cl^– and ClO^–

Sodium salt of an organic acid 'X' produces effervescence with conc. H₂SO₄. 'X' reacts with the acidified aqueous CaCl2 solution to give a white precipitate which decolourises acidic solution of KMnO₄. 'X' is

• C₆H₅COONa

• HCOONa

• Na₂C₂O₄

• Na₂C₂O₄

Which of the following species is not paramagnetic

• NO

• CO

• O₂

• O₂

The freezing point of benzene decreases by 0.45°C when 0.2 g of acetic acid is added to 20 g of benzene. If acetic acid associates to form a dimer in benzene, percentage association of acetic acid in benzene will be
(K_f for benzene = 5.12 K kg mol^–1)

• 64.6% 

• 80.4%

• 74.6%

• 74.6%

On treatment of 100 mL of 0.1 M solution of CoCl₃ . 6H₂O with excess AgNO₃; 1.2 × 10²² ions are precipitated. The complex is

• [Co(H₂O)₄ Cl₂]Cl.2H₂O

• [Co(H₂O)₃Cl₃].3H₂O

• [Co(H₂O)₆]Cl₃

• [Co(H₂O)₆]Cl₃

1 gram of a carbonate (M₂CO₃) on treatment with excess HCl produces 0.01186 mole of CO₂. The molar mass of M₂CO₃ in g mol^-1 is

• 1186

• 84.3

• 118.6

• 118.6