Compound C is a pink crystalline solid containing two cations and one anion.
Three tests were carried out on C. The observation made for each test was recorded in the table.
i) Complete the statements in the inference column by writing the names or formulae of the species.
(6)
Test | Observation | Inference |
Test 1 Aqueous sodium hydroxide was added to solid C and the mixture warmed The gas evolved was tested with damp red litmus paper | The red litmus paper turned blue | The gas evolved was .................... One of the cations in C is .................... |
Test 2 Concentrated hydrochloric acid was added to an aqueous solution of C | The pink solution turned blue | The other cation in C is .................... The formula of the complex ion in the blue solution is .................... |
Test 3 Dilute hydrochloric acid and aqueous barium chloride were added to an aqueous solution of C | A white precipitate formed | The white precipitate is .................... The anion in C is .................... |
ii) Use the results of the tests in (a)(i) to give a formula of C.
Do not include water of crystallisation.
(1)
Write the ionic equation for the reaction between the cation in C and sodium hydroxide producing the gas in Test 1.
State symbols are not required.
State the type of reaction occurring in Test 2.
Give a reason why dilute hydrochloric acid is needed in Test 3.
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