See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Acid Strength Comparison **Step 1: Identify the compounds and their acidic nature** - $RCOOH$ = Carboxylic acid (strongest acid) - $HOH$ = Water (weak acid) - $ROH$ = Alcohol (extremely weak acid) - $HC \equiv CH$ = Alkyne/Acetylene (extremely weak acid, essentially non-acidic) **Step 2: Compare acid strengths** **Carboxylic acids ($RCOOH$):** Most acidic due to resonance stabilization of the conjugate base ($RCOO^-$). The negative charge is delocalized over two oxygen atoms. **Water ($HOH$):** Weakly acidic (autoionization); $K_a \approx 10^{-16}$ at 25°C. **Alcohols ($ROH$):** Much weaker than water; the conjugate base ($RO^-$) is poorly stabilized due to the electron-donating alkyl group. $K_a \approx 10^{-16}$ to $10^{-18}$. **Alkynes ($HC \equiv CH$):** Virtually non-acidic as a traditional acid; the $sp$-hybridized carbon is very electronegative, making the proton hard to remove. Essentially a non-acid in aqueous conditions. **Step 3: Verify the order** $$RCOOH > HOH > ROH > HC \equiv CH$$ This matches **option (B)**. **Why others are wrong:** - (A): Incorrectly places $ROH$ above $HOH$ - (C): Incorrectly places $HC \equiv CH$ above $ROH$ - (D): Incorrectly places $HC \equiv CH$ above $HOH$