Explain why? [5 MARKS]
(a) Anhydrous HCl is a poor conductor while aq. HCl is an excellent conductor of electricity.
(b) Only a very dilute solution of hydrogen chloride in water can be concentrated by boiling the solution while a very concentrated solution would become less concentrated when boiled.
(c) When the stopper of a bottle full of hydrogen chloride gas is opened, there are fumes in the air.

Open in App

Solution

a) 2 Marks
b) 1 Mark
c) 2 Marks

(a) It is so because anhydrous HCI is a covalent compound and there are no ions present in it but in aqueous HCI ions are present.
HCI + $H_{2} O \to H_{3} O^{+} + C I^{-}$
Thus, the aqueous HCI conducts electric current.

(b) It is so because in the first case, the vapour evolved consists mostly of vapours of water but when conc. HCI is boiled, its vapour consists of mostly the molecules of HCI.

(c) It is due to the formation of hydrochloric acid on reacting with atmospheric water vapour as it is highly soluble in water. These droplets of liquid hydrochloric acid appear like fumes.

Suggest Corrections

Similar questions

Only a very dilute solution of hydrogen chloride in water can be concentrated by boiling the solution while a very concentrated solution would become less concentrated when boiled explain why?

Explain, why (or give reasons for)
(i) In the laboratory preparation of hydrogen chloride from sodium chloride, the gas can be obtained below 200°C or above. But the lower temperature is preferred.
(ii) Hydrogen chloride is not collected over water.
(iii) Hydrochloric acid cannot be concentrated above 22.2% by boiling.
(iv) HCl gas does not conduct electricity, but hydrochloric acid conducts electricity.
(v) Only a very dilute solution of hydrogen chloride in water can be concentrated by boiling the solution while a very concentrated solution would become less concentrated when boiled.
(vi) When the stopper of a bottle full of HCl gas is opened there are fumes in the air.
(vii) A solution of HCl gas in water turns blue litmus red and conducts electricity, while HCl gas dissolves in toluene and it has no effect on litmus and does not conduct electricity.
(viii) An aqueous solution of chlorine is acidic in nature.

Explain why :

(a) anhydrous HCl is a poor conductor while aqueous HCl is an excellent conductor.
(b) when the stopper of a bottle full of hydrogen chloride gas is opened there are fumes in the air.
(c) a solution of hydrogen chloride in water turns blue litmus red and conducts electricity, while a solution of the same gas in toluene :
(i) has no effect on litmus, and
(ii) does not conduct electricity.
(d) thick white fumes are formed when a glass rod dipped in $N H_{4} O H$ is brought near the mouth of a bottle full of HCl gas.
(e) dry hydrogen chloride gas does not affect a dry strip of blue litmus paper but it turns red in the presence of a drop of water.

(f) hydrogen chloride gas is not collected over water.

Q. It has been observed that gaseous hydrogen chloride is a very poor conductor of electricity but a solution of hydrogen chloride gas in water is a good conductor of electricity. This is due to the fact that

When the stopper of a bottle full of hydrogen chloride gas is opened, fumes can be seen coming out. Why does this happen?

Join BYJU'S Learning Program