Test for Cations

Question 1

Al 3+ in NaOH

Answer 1

white ppt, soluble in excess, colorless solution

Question 2

Al 3+ in ammonia

Answer 2

white ppt, insoluble in excess

Question 3

Ammonium in NaOH

Answer 3

Ammonia produced on warming

Question 4

Calcium in NaOH

Answer 4

white ppt, insoluble in excess

Question 5

Calcium in ammonia

Answer 5

no ppt/very slight white ppt

Question 6

Chromium (iii) in NaOH

Answer 6

green ppt, soluble in excess

Question 7

Chromium (iii) in ammonia

Answer 7

Green ppt, insoluble in excess

Question 8

Copper (ii) in NaOH

Answer 8

light blue ppt, insoluble in excess

Question 9

Copper (ii) in ammonia

Answer 9

light blue ppt, soluble in excess, giving a dark blue solution

Question 10

Iron (ii) in NaOH

Answer 10

green ppt, insoluble in excess, ppt turns brown near surface on standing

Question 11

Iron (ii) in ammonia

Answer 11

green ppt, insoluble in excess, ppt turns brown near surface on standing

Question 12

Iron (iii) in NaOH

Answer 12

red-brown ppt, insoluble in excess

Question 13

Iron (iii) in ammonia

Answer 13

red-brown ppt, insoluble in excess

Question 14

Zinc in NaOH

Answer 14

white ppt, soluble in excess, giving a colorless solution

Question 15

Zinc in ammonia

Answer 15

white ppt, soluble in excess, giving a colorless solution