JAMB Chemistry 2015 Paper

Concept:Carboxylic acids react with hydrogen trioxocarbonate(IV) salts to liberate carbon dioxide gas, while alcohols do not show this reaction.Explanation:Ethanoic acid ($\mathrm{CH_3COOH}$) is acidic because it contains a carboxyl group.It reacts with sodium hydrogen trioxocarbonate(IV) ($\mathrm{NaHCO_3}$) to produce carbon dioxide gas.The release of $\mathrm{CO_2}$ appears as effervescence or brisk bubbling.The reaction is: $\mathrm{CH_3COOH + NaHCO_3 \rightarrow CH_3COONa + H_2O + CO_2}$.Ethanol ($\mathrm{C_2H_5OH}$) is not acidic, so it does not react with $\mathrm{NaHCO_3}$.No gas bubbles are seen when ethanol is added to sodium hydrogen trioxocarbonate(IV).Bromine water, Fehling’s solution, and ammoniacal silver trioxonitrate(V) are not suitable for this simple acid–base distinction.Answer:C. sodium hydrogen trioxocarbonate (IV)