Question

Make a solution of the unknown substance: add sodium hydroxide solution or ammonium hydroxide solution, make observations and give your deduction. Warning the mixture may be needed. Choose from substances containing ca2+, cu2+, Fe2+, Fe3+ Pb2+ zn2+ NH4+​

Answer 1

Quedtion

Make a solution of the unknown substance: add sodium hydroxide solution or ammonium hydroxide solution, make observations and give your deduction. Warning the mixture may be needed. Choose from substances containing ca2+, cu2+, Fe2+, Fe3+ Pb2+ zn2+ NH4+

ANSWER

(i) A bluish white precipitate appears which dissolves in excess of NH

4

OH and give an inky blue solution of tetra-amino copper sulphate.

(ii) A gelatinous white precipitate appears which dissolves in excess of NH

4

OH and give a clear transparent colourless solution of tetraamine zinc sulphate.