question_answer

  It has been observed that dry hydrogen chloride gas does not turn blue litmus red whereas hydrochloric acid does. Explain this observation with the help of an activity and state the reason behind it.  

Answer:

                  Activity 1 g solid NaCI is taken in a clean and dry test tube as setup in the apparatus as shown Some concentrated sulphuric acid is added to the test tube. Then, with the help of dry and wet litmus papers, the gas coming out of the tube is tested.                                                   (3) Observation It is observed that the colour of dry litmus paper does not change while the colour of moist litmus paper changes from blue to red. This shows that dry HCl gas does not show acidic character whereas HCl solution shows. (1)