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

Be and Mg did not give flame colour because: 

1. Energy released by excited electron falls in visible region.

2. Energy released by excited electron does not fall in visible region

3. s-s transition.

4. Charge transfer.

An alkali metals that forms only the normal oxide M₂O on heating in air is-

1. Rb

2. K

3. Li

4. Na

 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
$\mathrm{}$

The correct order of  thermal stability of carbonates of Group 2 elements is-

1. ${\mathrm{BeCO}}_3<{\mathrm{MgCO}}_3<{\mathrm{CaCO}}_3<Sr{\mathrm{CO}}_3<{\mathrm{BaCO}}_3$

2. ${\mathrm{BeCO}}_3<{\mathrm{MgCO}}_3<{\mathrm{BaCO}}_3<{\mathrm{SrCO}}_3<{\mathrm{CaCO}}_3$

3. ${\mathrm{BaCO}}_3<{\mathrm{MgCO}}_3<{\mathrm{CaCO}}_3<Sr{\mathrm{CO}}_3<{\mathrm{BeCO}}_3$

4. ${\mathrm{BaCO}}_3<{\mathrm{CaCO}}_3<{\mathrm{MgCO}}_3<{\mathrm{SrCO}}_3<{\mathrm{BeCO}}_3$

Alkali and alkaline earth metals cannot be obtained by chemical reduction method because they are the strongest :

1. Oxidizing agents.

2. Reducing agents.

3. Hydrating agents.

4. Drying agents.

Potassium carbonate cannot be prepared by the Solvay process because -

Lithium salts are generally hydrated because they have :

1. High polarizing power.

2. High ionization enthalpy.

3. High electronegativity.

4. Low polarizing power.

The incorrect statement among the following is-