Chemistry
(a) Name an element which reacts with hydrogen to form compound which is strongly acidic in water.
(b) Explain why dilute hydrochloric acid cannot be concentrated by boiling beyond 22.2%
Answer
(a) Chlorine, It forms HCl which is strongly acidic.
H2 + Cl2 ⟶ 2HCl
(b) Hydrochloric acid forms a constant boiling mixture at 110°C, 22.2% by weight. On boiling further, the mixture evolves out the vapours of both acid and water in the same proportion as in the liquid.
Hence, dilute HCl cannot be concentrated beyond 22.2% by boiling.
Related Questions
State your observations:
(a) HCl gas is passed through lead nitrate solution and the mixture is heated.
(b) Hydrochloric acid is added to silver nitrate solution.
(c) Ammonium hydroxide solution is added to the resultant product of part (b).
Distinguish by using HCl.
(a) Lead nitrate solution and silver nitrate solution.
(b) Potassium sulphite and potassium sulphide.
The following questions pertain to the laboratory preparation of hydrogen chloride gas:
(i) Write the equation for it's preparation mentioning the condition required.
(ii) Name the drying agent used in the above preparation and give a reason for the choice.
(iii) State a safety precaution taken during the preparation of hydrochloric acid.
Identify the gas evolved and give the chemical test when dilute hydrochloric acid reacts with :
(i) Sodium sulphite.
(ii) Iron [II] sulphide.