Alkaline earth metals form hydrated crystalline solids such as $MgC{l}_2.6H_{2}O, CaC{l}_2.6H_{2}O$. This is due to-

(1) Smaller ionic size

(2) Increased charge on ions

(3) Higher hydration enthalpies

(4) High oxidation potential

A chloride dissolves appreciably in cold water. When placed in a platinum wire in Bunsen flame no distinctive colour is noticed. Which cation could be present –

(1) $B{e}^{2+}$                                         

(2) $B{a}^{2+}$

(3) $P{b}^{2+}$                                         

(4) $C{a}^{2+}$

Which of the following is a false statement-

(1) Sodium oxide is more basic then magnesium oxide.

(2) Beryllium oxide is amphoteric

(3) The thermal stability of beryllium carbonate is more than that of calcium carbonate

(4) Beryllium is amphoteric

Which alkali metal has the lowest melting point and exists as a liquid –

(1) Na                                                             

(2) K 

(3) Rb                                                             

(4) Cs

Two metals X and Y form covalent halides. Both halides can act as Lewis acids and a catalyst in Friedel Crafts reaction. Halide of X is polymer in the solid state and a dimer in the vapour state which decomposes to monomer at 1200 K. However, halide of Y is a dimer in vapour state and becomes ionic in polar solvent. X and Y are respectively.

(A) Be, Al                                             

(B) Al, Be

(C) Be, Ca                                             

(D) Mg, Ca

Solubility of sulphates in water decreases from $MgS{O}_4$ to $BaS{O}_4$. It is due to the fact that –

(1) Ionic nature increases

(2) Size of $M^{2+}$ ion increases

(3) Lattice energy decrease

(4) Hydration enthalpy of $M^{2+}$ ions decreases

In the Solvay process of manufacturing sodium carbonate, the raw materials used are :

1. Aqueous NaOH, ${\mathrm{NH}}_3$ and ${\mathrm{CO}}_2$

2. Molten NaOH, ${\mathrm{NH}}_3$ and CO

3. Brine NaCl, ${\mathrm{NH}}_3$ and CO

4. Brine NaCl, ${\mathrm{NH}}_3$ and ${\mathrm{CO}}_2$

Blue colour of the solution of alkali metal in ammonia is due to the presence of-

1. $M^{-}$atoms                                         

2. $M^{+}$ ions 

3. Solvated anions                             

4. Solvated electrons

The compound X on heating gives a colourless gas. The residue is dissolved in water to obtain Y. Excess of $C{O}_2$ is bubbled through aqueous solution of Y, Z is formed. Z on gentle heating gives back X. The compound X is-

(1) $CaC{O}_3$                                           

(2) $N{a}_{2}C{O}_3$

(3) $CaS{O}_4.2H_{2}O$                                 

(4) $K_{2}C{O}_3$

Assertion : s-block elements do not occur free in nature

Reason :  s-block elements are highly electropositive in nature.