Which of the following represents the atomic mass of element X in an acid with the molecular formula HXO₂, if 0.0242 mol of the acid has a mass of 1.657 g?

1.	35.5	2.	28.1
3.	128	4.	19.0

The sulphate of the metal M contains 9.87% of M. This sulphate is isomorphous with ${\mathrm{ZnSO}}_4.7{\mathrm{H}}_2\mathrm{O}$. What is the atomic weight of M?

1.  40.3

2.  36.3

3.  24.3

4.  11.3

Sulphur burns according to the reaction

 $\frac{1}{8}{\mathrm{S}}_8\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)$ $\stackrel{}{\to }$ ${\mathrm{SO}}_2\left(\mathrm{g}\right)$
What volume of air, at 1 atm and 273 K, containing 21%  oxygen by volume is required to completely burn sulphur $\left({\mathrm{S}}_8\right)$ present in 200 g of the sample?
(This sample contains 20% inert material which does not burn)

1.  23.52 litre

2.  320 litre

3.  112 litre

4.  533.33 litre

100 mL of H₂SO₄ solution having molarity 1 M and density 1.5 g mL⁻¹ is mixed with 400 mL water.
If the density of the final solution is 1.25 g mL⁻¹, calculate the molarity of the final H₂SO₄ solution.

Which of the following combinations illustrates the law of reciprocal proportions?
1. \(\mathrm{N}_2 \mathrm{O}_3, \mathrm{~N}_2 \mathrm{O}_4, \mathrm{~N}_2 \mathrm{O}_5 \)
2. \(\mathrm{NaCl}, \mathrm{NaBr}, \mathrm{Nal}\)
3. \(\mathrm{CS}_2, \mathrm{CO}_2, \mathrm{SO}_2 \)
4. \(\mathrm{PH}_3, \mathrm{P}_2 \mathrm{O}_3, \mathrm{P}_2 \mathrm{O}_5\)

Which of the following is dependent on temperature?

A mixture containing 2.3 g of formic acid (HCOOH) and 4.5 g of oxalic acid (H₂C₂O₄) is
heated with concentrated H₂SO₄. The gases evolved are passed through KOH pellets.

Calculate the mass of the gas that remains unabsorbed by KOH.

1.  1.4

2.  3.0

3.  2.8

4.  4.4

A 20.0 g impure sample of magnesium carbonate is heated completely and produces 8.0 g of magnesium oxide along with carbon dioxide.
Given: Atomic mass of Mg = 24
What is the percentage purity of MgCO₃ in the sample?