10 g of a silver coin, when dissolved completely in excess of conc. HNO₃ gives 8.5 g of silver nitrate.
The percentage purity of the coin is:
(Molar mass of silver is 108g)
 

1.	25%	2.	54%
3.	67%	4.	100%

Calculate the number of moles of oxygen (O) atoms in 126 amu of HNO₃. 

1.  2

2.  $\frac{2}{{\mathrm{N}}_{\mathrm{A}}}$

3.  6

4.  $\frac{6}{{\mathrm{N}}_{\mathrm{A}}}$

When 22.4 L of H₂ (g) is mixed with 11.2 L of Cl₂ (g), each at STP, the moles of HCl(g) formed is equal to -

Calculate the mass percentages of sodium (Na), sulfur (S), and oxygen (O), respectively, in sodium sulfate (Na₂SO₄).

1. 32.4%, 45.05% and 22.6%

2. 22.6%, 45.05% and 32.4%

3. 32.4%, 22.6% and 45.05%

4. 45.05%, 32.4% and 22.6%

The amount of copper (in grams) that can be obtained from 100 g of copper sulphate (CuSO₄) is:

1. Fe₃O₂

2. Fe₂O₂

3. Fe₂O₃

4. Fe₃O₄

20 g of sugar is dissolved in enough water to make a final volume of 2L. The concentration of sugar (C₁₂H₂₂O₁₁) in mol L^–1  will be:

1. 0.29 mol/L

2. 0.029 mol/L

3. 0.35 mol/L

4. 0.032 mol/L