Choose the correct answer:

Hydrogen chloride gas being highly soluble in water is dried by :

1. Anhydrous calcium chloride
2. Phosphorous pentaoxide
3. Quick lime
4. Conc. sulphuric acid.

(i) State the salt and the acid, used in the laboratory preparation of hydrogen chloride.

(ii) Give the equation for the preparation.

(iii) State a method to prove that the gas jar used for collection of HCl gas is filled with hydrogen chloride.

(iv) Observing the method of collection of the gas, state what you can tell about the density of hydrogen chloride.

State your observation when :
A glass rod dipped in NH₄OH soln. is brought near an open bottle containing conc. HCl

Name two gases which can be used in the study of the fountain experiment. State the common property demonstrated by the fountain experiment ?