The purification method based on the following physical transformation is:

Identify correct statements :

(A) Primary amines do not give diazonium salts when treated with $\mathrm{NaNO}_2$ in acidic condition.

(B) Aliphatic and aromatic primary amines on heating with $\mathrm{CHCl}_3$ and ethanolic KOH form carbylamines.

(C) Secondary and tertiary amines also give carbylamine test.

(D) Benzenesulfonyl chloride is known as Hinsberg's reagent.

(E) Tertiary amines reacts with benzenesulfonyl chloride very easily.

Choose the correct answer from the options given below :

Identify the inorganic sulphides that are yellow in colour :

(A) $(NH_4)_2S$

(B) $PbS$

(C) $CuS$

(D) $As_2S_3$

(E) $As_2S_5$

Choose the correct answer from the options given below :

Consider an elementary reaction

$$ \mathrm{A}(\mathrm{~g})+\mathrm{B}(\mathrm{~g}) \rightarrow \mathrm{C}(\mathrm{~g})+\mathrm{D}(\mathrm{~g}) $$

If the volume of reaction mixture is suddenly reduced to $\frac{1}{3}$ of its initial volume, the reaction rate will become ' $x^{\prime}$ times of the original reaction rate. The value of $x$ is :