A compound 'Z' with molecular formula C3H4O4 is heated to produce compound 'Y' and CO2 gas. Heating of compound 'Y' with P2O5 forms compound 'X' and water molecule. Identify the compound 'X'. a)…

The given molecular formula of compound Z is $\mathrm{C}{}_3\mathrm{H}{}_4\mathrm{O}{}_4$. When heated, it decomposes to form Y and $\mathrm{CO}{}_2$ gas. This suggests that Z is likely a dicarboxylic acid (since $\mathrm{CO}{}_2$ is released upon heating, indicating decarboxylation).

The only dicarboxylic acid with the formula $\mathrm{C}{}_3\mathrm{H}{}_4\mathrm{O}{}_4$ is malonic acid ($\mathrm{HOOC}-\mathrm{CH}{}_2-\mathrm{COOH}$). Upon heating, malonic acid decomposes to form ethanoic acid (acetic acid, $\mathrm{CH}{}_3\mathrm{COOH}$) and $\mathrm{CO}{}_2$:

C₃H₄O₄malonic acidheatacetic acidacetic acid+CO₂

$$\mathrm{HOOC}-\mathrm{CH}{}_2-\mathrm{COOH}\to \mathrm{CH}{}_3\mathrm{COOH}+\mathrm{CO}{}_2$$

Thus, Y is ethanoic acid ($\mathrm{CH}{}_3\mathrm{COOH}$).

When Y (ethanoic acid) is heated with $\mathrm{P}{}_2\mathrm{O}{}_5$ (a dehydrating agent), it forms ethanoic anhydride ($(\mathrm{CH}{}_3\mathrm{CO}){}_2\mathrm{O}$) and water:

acetic acidacetic acidP₂O₅ (dehydrating agent)acetic anhydrideacetic anhydride+H₂O

$$2\mathrm{CH}{}_3\mathrm{COOH}\to (\mathrm{CH}{}_3\mathrm{CO}){}_2\mathrm{O}+\mathrm{H}{}_2\mathrm{O}$$

Therefore, the compound X is ethanoic anhydride.

Answer: b) Ethanoic anhydride