Question

A certain compound $X$ imparts a golden yellow flame. When zinc powder is heated with concentrated solution of $X$, $H_2$ gas is evolved. $X$ combines with $CO_2$ to give a salt $Y$. $Y$ is a hydrated salt which on reaction with $HCl$ or excess of $CO_2$ gives another salt $Z$ which is an important part of baking powder. Identify $X$, $Y$ and $Z$.

• A. a
• B. b
• C. c
• D. d

Answer 1

Answer: (A)

a

Answer 2

${Zn +}$ $\underset{\text{(X)}}{ {2NaOH}}$ ${ \to Na2ZnO2 +H2}$ $\underset{\text{(X)}}{ {2NaOH}}$ $\,+ \, {CO2 \to}$ $\underset{\text{(Y)}}{ {Na2CO3}} {\,+ H2O}$ $\underset{\text{(Y)}}{ {Na2CO3}\,+} {HCl \to}$ $\underset{\text{(Z)}}{ {NaHCO3}}\,+ {NaCl}$ $\underset{\text{(Y)}}{ {Na2CO3}}+\, {CO2 +H2O \to}$ $\underset{\text{(Z)}}{ {2NaHCO3}}$