Unit 6

Question 1

Chromium in aqueous solution

Answer 1

Green

Question 2

Chromium in sodium hydroxide and excess as well

Answer 2

Green precipitate

In excess:
Precipitate dissolves
Forming a green solution

Question 3

Chromium in aqueous ammonia and excess

Answer 3

Green precipitate

In excess:
Precipitate dissolves
Forming yellow solution

Question 4

CO2+ aqueous solution

Answer 4

Pink

Question 5

Cobalt in sodium hydroxide and in excess

Answer 5

Blue precipitate
(Turns pink on exposure to air)

In excess:
Insoluble

Question 6

Cobalt in aqueous ammonia no in excess

Answer 6

Blue precipitate (turns pink exposure to air)

In excess :
Forms pale yellow solution ( turns brown on exposure)

Question 7

Manganese in aqueous solution

Answer 7

Very pale pink

Question 8

Manganese in sodium hydroxide and excess

Answer 8

Off white precipitate that turns (brown) on standing in air

In excess:
Insoluble in excess

Question 9

Manganese in aqueous ammonia and aqueous ammonia

Answer 9

Off white precipitate and turns brown on standing in air

IN excess:
Precipitate insoluble in excess

Question 10

Fe2+ in aqueous solution

Answer 10

Pale green solution

Question 11

Fe2+ in sodium hydroxide and in excess

Answer 11

Pale green precipitate

In excess:
Precipitate in insoluble

Question 12

Fe2+ in aqueous ammonia and in excess

Answer 12

Green precipitate that turns brown on standing in air

In excess
Precipitate is insoluble

Question 13

Fe3+ aqueous solution

Answer 13

Yellow

Question 14

Fe3+ sodium hydroxide and in excess

Answer 14

Red brown precipitate

In excess
Precipitate is insoluble

Question 15

Fe3+ in aqueous ammonia

Answer 15

Red brown precipitate

In excess
Precipitate is insoluble

Question 16

Ni2+ aqueous solution

Answer 16

Green

Question 17

Ni2+ sodium hydroxide and excess

Answer 17

Green precipitate

In excess
Precipitate is insoluble

Question 18

Ni2+ aqueous ammonia and in excess

Answer 18

Green precipitate

In excess
Precipitate dissolves
Forming a blue solution

Question 19

Cu2+ aqueous solution

Answer 19

Blue solution

Question 20

Cu2+ sodium hydroxide and in excess

Answer 20

Blue precipitate

In excess
Precipitate is insoluble

Question 21

Cu2+ in aqueous ammonia and in excess

Answer 21

Blue precipitate

In excess
Precipitate dissolves
Forming deep blue solution

Question 22

Zn2+ aqueous solution

Answer 22

Colourless

Question 23

Zn2+ sodium hydroxide and in excess

Answer 23

White precipitate

In excess
Precipitate dissolves
Forming a colourless solution

Question 24

Zn2+ and in aqueous ammonia and in excess

Answer 24

White precipitate

In excess
Precipitate dissolves forming a colourless solution