# On heating compound (A) gives a gas (B) which is constituent of air.

Question:

On heating compound (A) gives a gas (B) which is constituent of air. This gas when treated with $\mathrm{H}_{2}$ in the presence of a catalyst gives

another gas (C) which is basic in nature. (A) should not be:

1. $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$

2. $\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}$

3. $\mathrm{NaN}_{3}$

4. $\mathrm{NH}_{4} \mathrm{NO}_{2}$

Correct Option: , 2

Solution:

Basic gas $(\mathrm{C})$ must be ammonia $\left(\mathrm{NH}_{3}\right)$. It means (B) gas should be $\mathrm{N}_{2}$ which is formed by heating of compound (A).

(1) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} \stackrel{\Delta}{\longrightarrow} \mathrm{N}_{2} \uparrow+\mathrm{Cr}_{2} \mathrm{O}_{3}+4 \mathrm{H}_{2} \mathrm{O} \uparrow$

(2) $\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2} \stackrel{\Delta}{\longrightarrow} \mathrm{PbO}+2 \mathrm{NO}_{2} \uparrow+\frac{1}{2} \mathrm{O}_{2} \uparrow$

(3) $2 \mathrm{NaN}_{3} \stackrel{\Delta}{\longrightarrow} 2 \mathrm{Na}+3 \mathrm{~N}_{2} \uparrow$

(4) $\mathrm{NH}_{4} \mathrm{NO}_{2} \stackrel{\Delta}{\longrightarrow} \mathrm{N}_{2} \uparrow+2 \mathrm{H}_{2} \mathrm{O} \uparrow$