The correct statement(s) about the structure of BeCl₂ is -
a. BeCl₂ (solid)- exists as polymer.
b. BeCl₂ (vapour)- exists as chlorobridged dimer.
c. BeCl2 has bent structure in the vapour phase.
1. a
2. a & b
3. b
4. b & c

Li₂CO₃ decomposes at a lower temperature because -

1. Lithium carbonate is not stable to heat.

2. Lithium carbonate is ionic in nature.

3. Lithium ion is unable to polarise carbonate ion.

4. Electropositive character of lithium is the highest.

The correct diagonal relation of  Li and Mg among the following is -

1. Both form solid bicarbonates.

2. Their oxides are less soluble in water.

3.Their carbonates are ionic in nature.

4. Both form peroxides and superoxides.

Sodium is less reactive than potassium because-

1. Potassium loses electron easily.

2. Sodium loses electron easily.

3. Size of sodium is larger than potassium.

4. Nuclear charge is more on potassium.

The characteristic of alkaline earth metals is that-

1. Their general oxidation state is +1

2. They have a smaller size than alkali metals.

3. They are electronegative in nature.

4. They are strong oxidizing agents.

The incorrect statement about alkali metals is -

1. They have low density.

2. They have high ionization enthalpy.

3. They are highly reactive.

4. They show photoelectric effect.

The most stable (thermally) carbonate of alkaline earth metal is-

1. MgCO₃

2. CaCO₃

3. SrCO₃

4. BaCO₃

The alkali metal that gives hydrated salts is - 

1. Li

2. Na

3. K

4. Cs

 Alkali metal with the lowest melting point is -

1. Na

2. K

3. Rb

4. Cs

The chemical formula of Plaster of Paris is:

1. ${\mathrm{CaSO}}_4.\frac{1}{2}{\mathrm{H}}_2\mathrm{O}$

2. ${\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}$

3. ${\mathrm{CaSO}}_4.{\mathrm{H}}_2\mathrm{O}$

4. 3CaSO₄.H₂O
$\mathrm{}$