Question

An elements X burns in nitrogen to give a compound Y which on reaction with water gives a compound Z and a gas with a pungent smell. Z can be used during construction nd white washing. When excess of $CO_{2}$ is bubbled through Z, a compounds p is formed which on heating decomposes to give a colourless, odourless gas. Identify X, Y, Z and P.

	X			Y				Z			P

• A. | Ca | | | $Ca_{3}N_{2}$ | | | | $Ca(OH)_{2}$ | | | $Ca(HCO_{3})_{2}$ | | | | |
• B. | Mg | | | MgO | | | | $Mg(OH)_{2}$ | | | $MgCO_{3}$ | | | | |
• C. | Ca | | | $Ca_{3}N_{2}$ | | | | $Ca(OH)_{2}$ | | | $CaCO_{3}$ | | | | |
• D. | Ca | | | CaO | | | | $Ca(OH)_{2}$ | | | $Ca(HCO_{3})_{2}$ | | | | |

Answer 1

: $\underset{(X)}{3Ca} + N_{2} \rightarrow \underset{(Y)}{Ca_{3}N_{2}}$

$Ca_{3}N_{2} + 6H_{2}O \rightarrow 3Ca(OH)_{2} + \underset{(gaswithapungentsmell)}{2NH_{3}}$

$\underset{(Z)}{Ca(OH)_{2}} + \underset{excess}{CO_{2}} \rightarrow \underset{(P)}{Ca(HCO_{3})_{2}}$

$\underset{(P)}{Ca(HCO_{3})_{2}}\overset{\quad heat\quad}{\rightarrow}CaCO_{3} + H_{2}O + CO_{2}$