State one relevant observation for each of the following.

Lead nitrate solution is treated with sodium hydroxide solution dropwise till it is in excess.

Give a chemical test to distinguish between the following pairs of chemicals.

Lead nitrate solution and zinc nitrate solution.

Give a chemical test to distinguish between the following pairs of chemicals.

Sodium chloride solution and sodium nitrate solution.

A chloride which forms a precipitate that is soluble in excess of ammonium hydroxide, is

Identity the salts $\mathrm{P}$ and $\mathrm{Q}$ from the observations given below:

On performing the flame test salt $\mathrm{P}$ produces a lilac coloured flame and its solution gives a white precipitate with silver nitrate solution, which is soluble in ammonium hydroxide solution.

Identity the salts $\mathrm{P}$ and $\mathrm{Q}$ from the observations given below:

When dilute $\mathrm{H}\mathrm{C}\mathrm{l}$ is added to a salt $\mathrm{Q}$, a brisk effervescence is produced and the gas turns lime water milky. When $\mathrm{N}{\mathrm{H}}_4\mathrm{O}\mathrm{H}$ solution is added to the above mixture (after adding dilute $\mathrm{H}\mathrm{C}\mathrm{l}$), it produces a white precipitate which is soluble in excess $\mathrm{N}{\mathrm{H}}_4\mathrm{O}\mathrm{H}$ solution.