(a)[1]
A sample of M is dissolved in water, producing a colourless solution. Suggest what conclusion can be made.
(b)[2]
Into a test-tube containing $1\text{ cm}^3$ of aqueous M, add a small volume of aqueous sodium hydroxide. A white precipitate is produced. The precipitate dissolves in excess aqueous sodium hydroxide. Suggest two cations which could be present in aqueous M.
(c)[2]
What further test should the student carry out with aqueous M to identify which of the two cations suggested in (b) is present in M? Give the test and observations.
(d)[3]
M is known to contain either chloride ions or iodide ions. Suggest a test that will show which of the two anions is present in M. Give the test and observations.