Questions: Which equation correctly represents the dissociation of a carboxylic acid in water? CH3COOH ⇌ CH3COO^- + H^+ CH3COOH + H2O ⇌ CH3COO^- + H3O^+ CH3COOH + H2O ⇌ CH3CHCOOH2^+ + OH^- CH3COOH + H3O^+ ⇌ CH3COOH2^+ + H2O CH3COOH + 2 H2O ⇌ CH3COO^2- + 2 H3O^+

Solution Steps

Carboxylic acids, such as acetic acid ($\mathrm{CH}_3\mathrm{COOH}$), dissociate in water to form a carboxylate ion ($\mathrm{CH}_3\mathrm{COO}^-$) and a hydronium ion ($\mathrm{H}_3\mathrm{O}^+$). This process involves the transfer of a proton ($\mathrm{H}^+$) from the carboxylic acid to a water molecule.

Let's analyze each given equation to determine which one correctly represents the dissociation of a carboxylic acid in water:

1. $\mathrm{CH}_3\mathrm{COOH} \rightleftharpoons \mathrm{CH}_3\mathrm{COO}^- + \mathrm{H}^+$

   • This equation shows the dissociation of acetic acid into acetate and a proton, but it does not involve water explicitly.

2. $\mathrm{CH}_3\mathrm{COOH} + \mathrm{H}_2\mathrm{O} \rightleftharpoons \mathrm{CH}_3\mathrm{COO}^- + \mathrm{H}_3\mathrm{O}^+$

   • This equation correctly represents the dissociation of acetic acid in water, forming acetate and hydronium ions.

3. $\mathrm{CH}_3\mathrm{COOH} + \mathrm{H}_2\mathrm{O} \rightleftharpoons \mathrm{CH}_3\mathrm{CHCOOH}_2^+ + \mathrm{OH}^-$

   • This equation incorrectly suggests the formation of a different ion and hydroxide, which is not typical for carboxylic acid dissociation.

4. $\mathrm{CH}_3\mathrm{COOH} + \mathrm{H}_3\mathrm{O}^+ \rightleftharpoons \mathrm{CH}_3\mathrm{COOH}_2^+ + \mathrm{H}_2\mathrm{O}$

   • This equation suggests protonation of acetic acid, which is not the dissociation process.

5. $\mathrm{CH}_3\mathrm{COOH} + 2 \mathrm{H}_2\mathrm{O} \rightleftharpoons \mathrm{CH}_3\mathrm{COO}^{2-} + 2 \mathrm{H}_3\mathrm{O}^+$

   • This equation incorrectly suggests the formation of a doubly charged acetate ion, which is not typical.

Final Answer