See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Acidity Order Analysis **Step 1: Identify the compound types** - $RCOOH$ = Carboxylic acid (strong organic acid) - $H_2CO_3$ = Carbonic acid (weak acid) - $C_6H_5OH$ = Phenol (very weak acid) - $ROH$ = Aliphatic alcohol (extremely weak, negligible acidity) **Step 2: Compare $pK_a$ values** - Carboxylic acids: $pK_a \approx 4-5$ (strongest acid) - Carbonic acid: $pK_a \approx 6.4$ (weak acid) - Phenol: $pK_a \approx 10$ (very weak acid) - Aliphatic alcohols: $pK_a \approx 15-16$ (essentially non-acidic) **Step 3: Order by decreasing acidity** Lower $pK_a$ = higher acidity, so: $$RCOOH > H_2CO_3 > C_6H_5OH > ROH$$ **Why this order?** - $RCOOH$ is strongest (electron-withdrawing carbonyl group stabilizes conjugate base) - $H_2CO_3$ is weaker but still acidic (resonance stabilization of $HCO_3^-$) - $C_6H_5OH$ is weakly acidic (aromatic ring provides some stabilization) - $ROH$ is non-acidic (no stabilization of alkoxide anion) **Answer: (A)** ✓