An industrial chemist is investigating an unknown crystalline residue found inside a chemical reactor. They carry out two diagnostic tests on an aqueous solution of the residue:
| Test | Result | |
|---|---|---|
| Test 1 | Dilute nitric acid is added, followed by silver nitrate solution | A cream precipitate forms |
| Test 2 | Sodium hydroxide solution is added dropwise, then in excess | A blue precipitate forms |
State the name of the cation shown to be present in the residue by the result of Test 2.
Practise Edexcel GCSE Chemistry Qualitative analysis: tests for ions with exam-style questions for Foundation and Higher tier. 127 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
