The reaction of $\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}$ and $\mathrm{NaCl}$ in water produces a precipitate that dissolves upon the addition of $\mathrm{HCl}$ of appropriate concentration. The dissolution of the precipitate is due to the formation of

A colourless aqueous solution contains nitrates of two metals, X and Y. When it was added to an aqueous solution of NaCl, a white precipitate was formed. This precipitate was found to be partly soluble in hot water to give a residue P and a solution Q. The residue P was soluble in aqueous NH₃ and also in excess sodium thiosulphate. The hot solution Q gave a yellow precipitate with KI. The metals X and Y, respectively, are

Upon heating $$KCl{O_3}$$ in the presence of catalytic amount of $$Mn{O_2},$$ a gas $$W$$ is formed. Excess amount of $$W$$ reacts with white phosphorous to give $$X.$$ The reaction of $$X$$ with pure $$HN{O_3}$$ gives $$Y$$ and $$Z.$$

$$Y$$ and $$Z$$ are, respectively

Upon heating $$KCl{O_3}$$ in the presence of catalytic amount of $$Mn{O_2},$$ a gas $$W$$ is formed. Excess amount of $$W$$ reacts with white phosphorous to give $$X.$$ The reaction of $$X$$ with pure $$HN{O_3}$$ gives $$Y$$ and $$Z.$$

$$W$$ and $$X$$ are, respectively