Solid M is a mixture. Describe the tests you would carry out to identify the cations and anions present in the mixture. In each case, state the observations you would expect to make and the conclusion

Here are the observations and inferences for the tests on solid M:

a) Place all of the solid in a boiling tube. Add about $\text{10 cm}^{3}$ of distilled water and shake thoroughly. Filter the mixture into another boiling tube. Retain the residue for test (2b) below.

Observations	Inferences
Solid M partially dissolves to form a colorless solution. A white residue remains.	Solid M contains a water-soluble component and a water-insoluble component. The soluble component is a colorless salt.

i) To a portion of the filtrate obtained in (a) above, add 2M sodium hydroxide drop wise until excess.

Observations	Inferences
A white precipitate forms. The precipitate dissolves in excess $\text{NaOH}$ to form a colorless solution.	$\text{Al}^{3+}$, $\text{Pb}^{2+}$, or $\text{Zn}^{2+}$ ions are present in the filtrate.

ii) To another portion of the filtrate, add ammonia solution drop wise until excess.

Observations	Inferences
A white precipitate forms. The precipitate dissolves in excess ammonia solution to form a colorless solution.	$\boxed{\text{Zn}^{2+} \text{ ions are present in the filtrate.}}$