See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Base Strength Order Analysis **Step 1: Understand base strength relationship** Base strength is inversely related to conjugate acid strength. Stronger conjugate acid → weaker base. $$\text{Base strength} \propto \frac{1}{K_a \text{ of conjugate acid}}$$ **Step 2: Identify conjugate acids** - $Cl^-$ ← conjugate acid: $HCl$ (very strong acid, $K_a \gg 1$) - $F^-$ ← conjugate acid: $HF$ (weak acid, $K_a = 6.8 \times 10^{-4}$) - $CH_3COO^-$ ← conjugate acid: $CH_3COOH$ (weak acid, $K_a = 1.8 \times 10^{-5}$) - $^-OH$ ← conjugate acid: $H_2O$ (extremely weak acid, $K_a \approx 10^{-16}$) **Step 3: Rank by conjugate acid strength** $$HCl \gg HF > CH_3COOH > H_2O$$ **Step 4: Invert to get base strength order** $$^-OH > CH_3COO^- > F^- > Cl^-$$ Or equivalently: $$Cl^- < F^- < CH_3COO^- < ^-OH$$ **Answer: (A)** is correct because it properly reflects that $^-OH$ is the strongest base (water is the weakest acid) and $Cl^-$ is the weakest base (HCl is the strongest conjugate acid).