chapter 7.  ELEMENTS OF GROUPS 16, 17 AND 18 class 12 chemistry textbook solution

3. Answer the following.

ix. How is hydrogen chloride prepared from sodium chloride ?


Hydrogen chloride (HCl) gas can be prepared from sodium chloride (NaCl) through a chemical reaction known as the salt-acid reaction. The process involves the reaction of sodium chloride with a strong acid, typically sulfuric acid (H2SO4). Here are the steps to prepare hydrogen chloride from sodium chloride:

Materials Needed:

  1. Sodium chloride (table salt, NaCl)
  2. Sulfuric acid (H2SO4)
  3. Distillation apparatus (including a round-bottom flask, condenser, and collection flask)
  4. Heat source (e.g., Bunsen burner or heating mantle)
  5. Tubing or rubber tubing
  6. Receiver flask or gas collection apparatus


  1. Set up a distillation apparatus. This typically includes a round-bottom flask connected to a condenser, which is then connected to a receiver flask or gas collection apparatus.

  2. Add a quantity of sodium chloride (NaCl) to the round-bottom flask. The amount of NaCl used will depend on the desired amount of hydrogen chloride gas to be generated.

  3. Carefully add concentrated sulfuric acid (H2SO4) to the round-bottom flask containing the sodium chloride. The sulfuric acid serves as the acid source for the reaction and will react with the salt to produce hydrogen chloride gas. The reaction is as follows:

    NaCl(s) + H2SO4(l) → NaHSO4(s) + HCl(g)

    Sodium chloride reacts with sulfuric acid to produce sodium hydrogen sulfate (NaHSO4) and hydrogen chloride gas (HCl).

  4. Heat the round-bottom flask containing the mixture gently. As the mixture heats up, hydrogen chloride gas is produced and carried over to the condenser.

  5. In the condenser, the hydrogen chloride gas is cooled and condensed into a liquid. It then flows into the receiver flask or gas collection apparatus.

  6. Collect the hydrogen chloride gas by allowing it to bubble through water or another suitable collection solution. Hydrogen chloride gas readily dissolves in water to form hydrochloric acid (HCl).

  7. The collected solution in the receiver flask will contain hydrochloric acid (HCl) that can be used for various chemical applications.

It’s essential to perform this procedure in a well-ventilated fume hood or a controlled environment because hydrogen chloride gas is highly corrosive and can form acidic fumes. Also, safety precautions, such as wearing appropriate protective gear (lab coat, safety goggles, gloves) and working with caution around strong acids, should be observed during the experiment.

chapter 7.  ELEMENTS OF GROUPS 16, 17 AND 18 Textbook Solution page 164