Chemistry · May / June 2021 · Paper 61 · Question 3

Solid E and solution F were analysed. Tests were done on each substance. tests on solid E tests observations test 1 About half of solid E was placed in a test‑tube and heated gently. steam was given off; condensation appeared near the mouth of the test‑tube The remaining solid E was dissolved in distilled water to produce solution E. The solution was divided into four equal portions in three test‑tubes and a boiling tube. test 2 About 1 cm3 of dilute nitric acid followed by a few drops of aqueous silver nitrate were added to the first portion of solution E. no visible change test 3 About 1 cm3 of dilute nitric acid followed by a few drops of aqueous barium nitrate were added to the second portion of solution E. white precipitate test 4 Excess aqueous ammonia was added to the third portion of solution E. white precipitate test 5 Aqueous sodium hydroxide was added dropwise and then in excess to the fourth portion of solution E in the boiling tube. white precipitate which dissolved in excess to form a colourless solution test 6 The product from test 5 was warmed gently and any gas given off was tested with damp red litmus paper. the red litmus paper turned blue

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