Name the acid used in the preparation of hydrogen chloride gas in the laboratory. Why is this particular acid preferred to other acids?

52.

Write the balanced chemical equation for the laboratory preparation of hydrogen chloride gas.

For the preparation of hydrochloric acid in the laboratory:

(i) Why is the direct absorption of hydrogen chloride gas in water not feasible?

(ii) What arrangement is done to dissolve hydrogen chloride gas in water?

For the electro-refining of copper :
(i) What is the cathode made up of?
(ii) Write the reaction that takes place at the anode.

The percentage composition of a gas is:

Nitrogen 82.35%, Hydrogen 17.64%. Find the empirical formula of the gas. [N = 14, H = 1]

Aluminium carbide reacts with water  according to the following equation:

${\mathrm{Al}}_4{\mathrm{C}}_3 + 12 {\mathrm{H}}_2\mathrm{O} \stackrel{ }{\to } 4 \mathrm{Al}(\mathrm{OH}{)}_3 + 3{\mathrm{CH}}_4$

(i) What mass of aluminium hydroxide is formed from 12g of aluminium carbide?
(ii) What volume of methane at s.t.p. is obtained from 12g of aluminium carbide?
[Relatively molecular weight of Al₄Cl₃ = 144 ; Al(OH)₃ = 78]

(i) If 150 cc of gas A contains X molecules, how many molecules of gas B will be present in 75 cc of B? The gases A and B are under the same conditions of temperature and pressure.

(ii) Name the law on which the above problem is based.

Name the main component of the following alloy:

Brass

Name the main component of the following alloy:

Duralumin

A compound X (having a vinegar-like smell) when treated with ethanol in the presence of the acid Z, gives a compound Y which has a fruity smell.

The reaction is: 

${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH} + \mathrm{X} \stackrel{\mathrm{z}}{\to } \mathrm{Y} + {\mathrm{H}}_2\mathrm{O}$

(i) Identify Y and Z.

(ii) Write the structural formula of X.

(iii) Name the above reaction.