Chemistry NCERT Exemplar Solutions Class 11th Chapter Three

The total number of unpaired electrons present in the complex K?[Cr(oxalate)?] is _____.

Complete combustion of 3 g of ethane gives x*10²² molecules of water. The value of x is _____. (Round off to the nearest integer).
[ Use : NA = 6.023 *10²³; Atomic masses in u: C:12.0,O:16.0; H:1.0]

2 molal solution of a weak acid HA has a freezing point of 3.885°C. The degree of dissociation of this acid is _____ * 10?³. (Round off to the nearest integer).
[ Given : Molal depression constant of water = 1.85 K kg mol?¹, Freezing point of pure water = 0°C]

2NO(g) + Cl?(g) ? 2NOCl(s)
This reaction was studied at -10°C and the following data was obtained

[NO]? and [Cl?]? are the initial concentrations and r? is the initial reaction rate. The overall order of the reaction is _____. (Round off to the nearest integer).

_____ grams of 3-Hydroxy propanal (MW = 74) must be dehydrated to produce 7.8g of acrolein (MW = 56) (C?H?O) if the percentage yield is 64. (Round off to the nearest integer).
[Given: Atomic masses: C: 12.0u, H:1.0u, O:16.0u]

For the reaction
2Fe³?(aq) + 2I?(aq) → 2Fe²?(aq) + I?(s)
The magnitude of the standard molar free energy change, ?rG° = ____ kJ (Round off to the nearest integer).
[Given: E°(Fe²?/Fe(s)) = -0.440V; E°(Fe³?/Fe(s)) = -0.036V; E°(I?/2I?) = 0.539V; F = 96500C]

AX is a covalent diatomic molecule where A and X are second row elements of periodic table. Based on molecular orbital theory, the bond order of AX is 2.5. The total number of electrons in AX is _____. (Round off to the nearest integer).

In order to prepare a buffer solution of pH 5.74, sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is 1.0 M, the concentration of sodium acetate in the buffer is _____ M. (Round off to the nearest integer).
[Given: pKa (acetic acid) = 4.74]

For the reaction C?H? → C?H? + H? the reaction enthalpy ?rH = ____ kJ mol?¹. (Round off to the nearest integer).
[ Given: Bond enthalpies in kJ mol?¹ : C-C: 347, C=C:611; C-H:414,H-H:436]

A reaction of 0.1 mole of Benzylamine with bromomethane gave 23g of Benzyl trimethyl ammonium bromide. The number of moles of bromomethane consumed in this reaction are n x 10?¹, when n=_____. (Round off to the nearest integer).
[Given: Atomic masses: C=12.0u, H:1.0u, N:14.0u, Br:80.0u]