A mixture of two solid compounds D and E was analysed. Solid D was a zinc salt which is soluble in water. Solid E was an insoluble metal carbonate. The tests on the mixture and some of the observations are in the following table.
Test 1: About half of the mixture of D and E was placed in a test-tube. The mixture was heated.
Observations: Green to black, condensation formed
The rest of the mixture of D and E was added to distilled water in a boiling tube. The contents of the tube were filtered. The filtrate and the residue were kept for the following tests.
a)
Complete observations for the following tests that were carried out on the residue
i)
Test 1:
The residue was transferred from the filter paper in to a test-tube. About 3 cm3 of dilute sulphuric acid was
added. The gas was tested with limewater.
Observations: ....................................................................................................................
[2]
ii)
Test 2:
The solution obtained in (c) was divided into two equal portions.
The first portion was added excess aqueous sodium hydroxide, a little at a time.
Observations: pale blue precipitate
To the second portion was added excess aqueous ammonia, a little at a time.
Observations: ....................................................................................................................
[4]