Among the following the least thermally stable carbonate is : 

$1.$ ${\mathrm{K}}_2{\mathrm{CO}}_3$

2. ${\mathrm{Na}}_2{\mathrm{CO}}_3$

3. ${\mathrm{BaCO}}_3$

4. ${\mathrm{Li}}_2{\mathrm{CO}}_3$

One mole of calcium phosphide upon reacting with water gives:

1. One mole of the phosphene.

2. Two moles of phosphoric acid.

3. Two moles of phosphine.

4. One mole of phosphorus pentaoxide.

Sodium nitrate decomposes above 800°C and does not give:

1. ${\mathrm{N}}_2$

2. ${\mathrm{O}}_2$

3. ${\mathrm{NO}}_2$

4. Na₂O

${\mathrm{KO}}_2$ is used in oxygen cylinders in space aircraft and submarines because it :

1. Absorbs ${\mathrm{CO}}_2$ and increases ${\mathrm{O}}_2$ content.

2. Eliminates moisture.

3. Absorbs ${\mathrm{CO}}_2$

4. Produces ${\mathrm{O}}_2$

Sodium in liquid ammonia is used as :

1. Oxidizing agent .

2. Reducing agent.

3. Hydrolyzing agent.

4. Precipitating agent.

A molecule among the following that has the highest hydration energy is -

1. MgCl₂

2. CaCl₂

3. BaCl₂

4. SrCl₂

In case of alkali metal halides, the ionic character increases in the order : 

1. MF < MCl < MBr < MI

2. MI < MBr < MCl < MF

3. MI < MBr < MF < MCl

4. None of the above.

Lithium shows a diagonal relationship with : 

1. Sodium

2. Magnesium

3. Calcium

4. Aluminium

The incorrect statement among the following is- 

1. Sodium metal is used in organic qualitative analysis.

2. Sodium carbonate is soluble in water and it is used in inorganic qualitative analysis.

3. Potassium carbonate can be prepared by the solvay process.

4. Aq. solution of potassium bicarbonate is a weak base.

The incorrect statement among the following is -

1. Li⁺ has minimum degree of hydration among alkali metal cations.

2. The oxidation state of K in KO₂ is +1

3. Sodium is used to make Na / Pb alloy.

4. MgSO₄ is readily soluble in water.