When a solid salt is heated with concentrated H ₂ SO ₄ , a colourless gas with a pungent odour is evolved. When a glass rod dipped in aqueous ammonia is brought near the mouth of the test tube, dense white fumes are observed. Identify the correct anion present in the salt :

Step-by-step solution

When a salt containing the chloride anion ( Cl ⁻ ) is heated with concentrated H ₂ SO ₄ , hydrogen chloride ( HCl ) gas is evolved. Cl ⁻ + H ₂ SO ₄ HCl + HSO ₄⁻ HCl is a colourless gas with a pungent smell. When a glass rod dipped in aqueous ammonia ( NH ₄ OH ) is brought near it, dense white fumes of ammonium chloride ( NH ₄ Cl ) are formed. HCl + NH ₃ NH ₄ Cl (dense white fumes) Bromide gives reddish-brown fumes of Br ₂ , nitrate gives brown fumes of NO ₂ , and sulphate does not react with concentrated H ₂ SO ₄ t