GCSE / O Levels Chemistry

40   Aqueous   sodium   hydroxide   is   used   to   identify   the   ions   present   in   aqueous   solutions   of compounds Q and R. The results are shown.  Q coloured solution before addition of aqueous sodium hydroxide after addition of a few drops of aqueous sodium hydroxide green precipitate R colourless solution before addition of aqueous sodium hydroxide after addition of aqueous sodium hydroxide gas given off heat  Which row is correct? ion in compound Q ion in compound R  A   Cr   3+   NH 4+  B   Cu   2+   CO 32–  C   Fe   2+   CO 32–  D   Fe   3+   NH 4+

Identification of Ions and Gases | 2023 - M/J - 5070/12 | Q40