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
$\mathrm{}$

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.

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

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

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.

The correct order of increasing thermal stability of K₂CO₃, MgCO₃, CaCO₃ and BeCO₃ is :

1. ${\mathrm{BeCO}}_3<{\mathrm{MgCO}}_3<{\mathrm{K}}_2{\mathrm{CO}}_3<{\mathrm{CaCO}}_3$

2. ${\mathrm{BeCO}}_3<{\mathrm{MgCO}}_3<{\mathrm{CaCO}}_3<{\mathrm{K}}_2{\mathrm{CO}}_3$

3. ${\mathrm{MgCO}}_3<{\mathrm{BeCO}}_3<{\mathrm{CaCO}}_3<{\mathrm{K}}_2{\mathrm{CO}}_3$

4. ${\mathrm{K}}_2{\mathrm{CO}}_3<{\mathrm{MgCO}}_3<{\mathrm{CaCO}}_3<{\mathrm{BeCO}}_3$

 An amphoteric hydroxide among the following is : 

1.  $\mathrm{Be}{\left(\mathrm{OH}\right)}_2$

2.  $\mathrm{Sr}{\left(\mathrm{OH}\right)}_2$

3.  $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$

4.  $\mathrm{Mg}{\left(\mathrm{OH}\right)}_2$