identification of cations

Question 1

aluminium after adding sodium hydroxide

Answer 1

white precipitate, dissolves in NaOH to form a colourless solution

Question 2

aluminium after adding ammonia solution

Answer 2

white precipitate, insoluble in excess ammonia and white precipitate remains

Question 3

ammonium after adding sodium hydroxide

Answer 3

ammonia produced if warmed

Question 4

ammonium after adding ammonia solution

Answer 4

nothing

Question 5

calcium after adding sodium hydroxide

Answer 5

white precipitate, insoluble so remains in excess NaOH

Question 6

calcium after adding ammonia solution

Answer 6

very faintly visible white precipitate

Question 7

chromium (III) after adding sodium hydroxide

Answer 7

green precipitate which forms a green solution in excess

Question 8

chromium (III) after adding ammonia solution

Answer 8

grey-green precipitate, insoluble in excess

Question 9

copper (II) after adding sodium hydroxide

Answer 9

light blue precipitate, insoluble in excess

Question 10

copper (II) after adding ammonia solution

Answer 10

light blue precipitate, soluble in excess to form a dark blue solution

Question 11

iron (II) after adding sodium hydroxide

Answer 11

green precipitate, insoluble in excess

Question 12

iron (II) after adding ammonia solution

Answer 12

green precipitate, insoluble in excess

Question 13

iron (III) after adding sodium hydroxide

Answer 13

red-brown precipitate, insoluble in excess

Question 14

iron (III) after adding ammonia solution

Answer 14

red-brown precipitate, insoluble in excess

Question 15

zinc after adding sodium hydroxide

Answer 15

white precipitate, dissolves in excess to form colourless solution

Question 16

zinc after adding ammonia solution

Answer 16

white precipitate, dissolves in excess to form colourless solution