Calcium carbide on hydrolysis forms — Hydrocarbons Chemistry Question

💡 Solution & Explanation

# Hydrolysis of Calcium Carbide **Step 1: Identify calcium carbide's structure** Calcium carbide is $CaC_2$, containing the carbide ion $C_2^{2-}$ (acetylide ion with a triple bond: $C \equiv C$). **Step 2: Write the hydrolysis reaction** $$CaC_2 + 2H_2O \rightarrow Ca(OH)_2 + C_2H_2$$ **Step 3: Identify the products** - **Calcium hydroxide**: $Ca(OH)_2$ (a white solid, moderately soluble base) - **Acetylene gas**: $C_2H_2$ (colorless, flammable gas with a characteristic pungent odor) **Step 4: Why this occurs** The $C \equiv C$ triple bond in the carbide ion is highly polarized and nucleophilic. Water molecules attack, breaking the $C$-$C$ bonds and forming $C_2H_2$ while $Ca^{2+}$ combines with $OH^-$ ions. **Answer: Calcium carbide hydrolyzes to form calcium hydroxide [$Ca(OH)_2$] and acetylene gas [$C_2H_2$]** — provided option D states this combination.