A student investigates solution W and copper(II) carbonate. (a) The tests the student does on W are shown in Table 3.1. Some of the observations for these tests are also shown. Table 3.1 tests on solution W observations 1 Add aqueous sodium hydroxide to W. solution remains colourless 2 Add dilute nitric acid, then add aqueous barium nitrate to W. white precipitate 3 Add dilute hydrochloric acid, then add aqueous silver nitrate to W. white precipitate 4 Flame test on W. no colour is observed

1. (a)(i)The student correctly concludes that ammonia is formed in test 1. Describe what else the student must have done to reach this conclusion.[3]
2. (a)(ii)State why the student cannot identify the anion in W from the observation in test 3.[1]
3. (a)(iii)State how the tests and observations show that W does not contain sodium ions.[1]
4. (a)(iv)Identify the cation and anion in W. cation ..................................................... anion .....................................................[2]
5. (b)(i)The student adds dilute hydrochloric acid to copper(II) carbonate. A gas and a solution are produced. State the observation that confirms the production of a gas.[1]
6. (b)(ii)Describe how to do a flame test to confirm the presence of copper(II) ions in the solution.[3]
7. (b)(iii)Describe one other method the student could use to confirm that the solution contains copper(II) ions.[3]