In a test tube containing a salt, a few drops of dilute H ₂ SO ₄ was added, which gave colourless vapours having the smell of vinegar. The vapours turned the blue litmus paper red. Identify the correct anion from the following :

Step-by-step solution

When a salt containing the acetate anion ( CH ₃ COO ⁻ ) is treated with dilute H ₂ SO ₄ , acetic acid ( CH ₃ COOH ) is formed. 2 CH ₃ COO ⁻ + H ₂ SO ₄ 2 CH ₃ COOH + SO ₄²⁻ Acetic acid vapours are colourless and have a characteristic smell of vinegar. Being acidic in nature, these vapours turn blue litmus paper red. Sulphide ( S ²⁻ ) gives H ₂ S gas which has a rotten egg smell. Sulphate ( SO ₄²⁻ ) does not react with dilute H ₂ SO ₄ . Carbonate ( CO ₃²⁻ ) gives CO ₂ gas which is odourless. Answer: Acetate, CH ₃ COO