NH4Cr(SO4)2⋅12H2O\text{NH}_4\text{Cr}(\text{SO}_4)_2 \cdot 12\text{H}_2\text{O}NH4Cr(SO4)2⋅12H2O is a hydrated 'double salt' known as ammonium chromium alum.
A student analyses a solution of this double salt using test tube tests.
Which row(s) gives/give correct result(s) for the stated test?
| Test | Observation | |
|---|---|---|
| 1 | Addition of excess NaOH(aq)\text{NaOH(aq)}NaOH(aq) | Green precipitate dissolves to form a green solution |
| 2 | Addition of acidified AgNO3(aq)\text{AgNO}_3\text{(aq)}AgNO3(aq) | White precipitate |
| 3 | Heating with NaOH(aq)\text{NaOH(aq)}NaOH(aq) | A gas is evolved that turns damp red litmus paper blue |
1, 2 and 3
Only 1 and 2
Only 1 and 3
Only 2 and 3
