JEE Main 2019 Revision || States of Matter and Solutions for JEE & BITSAT Exams

Question 1

A two-dimensional solid pattern formed by two different atoms X and Y is shown below. The black and white squares represent atoms X and Y, respectively. The simplest formula for the compound based on the unit cell from the pattern is

Question 2

An organic compound crystallizes in an ortho rhombic system with two molecules per unit cell. The unit cell dimensions are 12.05, 15.05 and 2.69Å. If the density of the crystal is 1.419 g cm^-3, then molar mass of compound will be

Question 3

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

Question 4

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:

Question 5

Ethylene glycol is used as an antifreeze in a cold climate. Mass of ethylene glycol which should be added to 4 kg of water to prevent it from freezing at –6 °C will be : (K_f for water = 1.86 K kg mol^-1, and molar mass of ethylene glycol = 62 g mol^-1)

Question 6

In a 0.2 molal aqueous solution of a weak acid HX, the degree of ionization is 0.3. Taking K_f for water as 1.85, the freezing point of the solution will be nearest to

Question 7

If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water (ΔT_f), when 0.01 mol of sodium sulphate is dissolved in 1 kg of water, is (K_f = 1.86 K kg mol^–1).

Question 8

In a face centered cubic lattice atoms A are at the corner points and atoms B at the face centered points. If atom B is missing from one of the face centered points, the formula of the ionic compound is :

Question 9

Which type of 'defect' has the presence of cations in the interstitial sites?

Question 10

If Z is a compressibility factor, van der Waals equation at low pressure can be written as:

Question 11

When does a gas deviate the most from its ideal behaviour?

Question 12

At very high pressures, the compressibility factor of one mole of a gas is given by:

Question 13

A 5.25% solution of a solution of a substance is isotonic with a 1.5% solution of urea (molar mass =
60 g mol^–1) in the same solvent. If the densities of both the solution are assumed to be equal to 1.0 g cm^–3, molar mass of the substance will be

Question 14

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4. The ratio of number of their molecule is :

Question 15

For the reaction,

and

are, respectively,

and

at 298 K. The equilibrium constant for the reaction at
298 K is: