# NEET Chemistry The s-Block Elements Questions Solved

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-

(A) $CaC{O}_{3}$

(B) $N{a}_{2}C{O}_{3}$

(C) $CaS{O}_{4}.2{H}_{2}O$

(D) ${K}_{2}C{O}_{3}$

(A).

$\underset{\left(Y\right)}{Ca{\left(OH\right)}_{2}}+\underset{\left(excess\right)}{C{O}_{2}}\to \underset{\left(Z\right)}{Ca{\left(HC{O}_{3}\right)}_{2}}$

$\underset{\left(Z\right)}{Ca{\left(HC{O}_{3}\right)}_{2}}\stackrel{∆}{\to }\underset{\left(X\right)}{CaC{O}_{3}}+{H}_{2}O+C{O}_{2}$

Difficulty Level:

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