H₃PO₄ is a tribasic acid and one of its salts is NaH₂PO₄. What volume of 1 M NaOH should be added to 12g NaH₂PO₄ (Molar mass 120) to exactly convert it into Na₃PO₄?

1. 100 mL

2. 300mL

3. 200mL

4. 80mL

A metal M forms a compound M₂HPO₄. The formula of the metal sulfate is:

1. M₂SO₄ 

2. MSO₄

3. M(SO₄${)}_2$

4. M₂(SO₄)₃

One mole of a mixture of CO and CO₂ requires exactly 20g of NaOH in solution for complete conversion of all the CO₂ into Na₂CO₃. How much NaOH would it require for conversion into Na₂CO₃, if the mixture (one mole) is completely oxidised to CO₂?

1. 60g

2. 80g

3. 40g

4. 20g

The oxide of metal contains 40% by mass of oxygen. The percentage of chlorine in the chloride of the metal is

1) 84.7

(2) 74.7

(3) 64.7

(4) 44.7

What volume of ${\mathrm{O}}_2\left(\mathrm{g}\right)$ measured at 1 atm and 273 K will be formed by the action of 100 mL of 0.5 N KMnO₄ on hydrogen peroxide in an acid solution? The skeleton equation for the reaction is
${\mathrm{KMnO}}_4+{\mathrm{H}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2{\mathrm{O}}_2$$\to K_{2}S{O}_4+MnS{O}_4+O_2+H_{2}O$

1.  0.12 litre

2.  0.028 litre

3.  0.56 litre

4.  1.12 litre