A metal [x] on heating on nitrogen gas gives [Y]. [Y] on treatment with ${\mathrm{H}}_2\mathrm{O}$ gives a colourless gas which when passed through ${\mathrm{CuSO}}_4$ solution gives a blue colour. [Y] is

(A) $\mathrm{Mg}{\left({\mathrm{NO}}_3\right)}_2$                                     

(B) ${\mathrm{Mg}}_3{\mathrm{N}}_2$

(C) ${\mathrm{NaN}}_3$                                             

(D) $\mathrm{MgO}$

The density of-

1. Na > K                                                     

2. Na = K

3. K > Na                                                     

4. Li > K

Lattice energy is lowest for –

(A) LiF                                                       

(B) NaCl

(C) KBr                                                       

(D) CsI

Which of the following halides has the highest melting point-

(A) NaCl                                           

(B) KCl

(C) NaBr                                           

(D) NaF

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