Chemistry
Explain why :
(a) hydrogen chloride gas is not collected over water.
(b) hydrogen chloride gas cannot be dried over quick lime.
(c) thick white fumes are formed when a glass rod dipped in NH4OH is brought near the mouth of a bottle full of HCl gas.
(d) HCl fumes in air.
Answer
(a) Hydrogen chloride gas is not collected over water since it is highly soluble in water.
(b) Quicklime [CaO] is alkaline in nature and it reacts with HCl forming the respective chloride. Hence, it can't be used as a drying agent.
(c) When a glass rod dipped in ammonium hydroxide (NH4OH) is brought near the mouth of a bottle full of HCl gas, then it leads to the formation of dense white fumes due to the production of ammonium chloride.
NH4OH + HCl ⟶ NH4Cl + H2O
(d) Hydrogen chloride gas fumes in moist air because it dissolves in water vapour present in air to form tiny droplets of hydrochloric acid, which appear as white fumes.
Related Questions
Draw a labelled diagram for the laboratory preparation of hydrogen chloride gas and answer the following.
(a) Name the acid used. Why is this particular acid preferred to other acids?
(b) Give the balanced equation for the reaction.
(c) Name the drying agent used in drying hydrogen chloride gas.
(d) Phosphorus pentoxide and calcium oxide are good drying agents, but they cannot be used to dry hydrogen chloride gas. Why?
In the laboratory preparation of hydrochloric acid, hydrogen chloride gas is dissolved in water.
(i) Draw a diagram to show the arrangement used for the absorption of HCl gas in water.
(ii) State why such an arrangement is necessary? Give two reasons for the same.
(iii) Write balanced chemical equations for the laboratory preparation of HCl gas when the reactants are :
(A) below 200°C
(B) above 200°C
With respect to the laboratory preparation of HCl gas, answer the following questions :
(a) Name the reactants used and the product(s) formed.
(b) Under what conditions do the reactants react?
(c) How is the gas identified?
(d) State the precautions to be taken.
Hydrogen chloride molecule is:
- Polar covalent
- Non polar
- Ionic
- Co-ordinate