Qualitative Analysis of Group 2 Cations

Question 1

Place 20 drops of each of the following aqueous solutions to separate centrifuge tubes:

Answer 1

0.2M Bi(NO3)3,
0.2M Cd(NO3)3,
0.2M Cu(NO3)2,
0.2M Sb(NO3)3,
0.2M Sn(NO3)2.

Question 2

Then add ____ of freshly prepared ___ to each centrifuge tube. Record your
observation.

Answer 2

5 drops ; 6M (NH4)^2S

Question 2

Centrifuge the mixtures and decant the supernatant liquid. Wash each of the precipitates with _____ and ______.

Answer 2

1 drop of 6 M NH4CI

20 drops of deionized water

Question 3

To the washed precipitates containing ____, add _______ and
_____ . Stir and boil the mixture in a hot water bath for __ minutes.

Answer 3

Bi3+, Cd3+ and Cu+2 ; 10 drops of DI water ; 10 drops of 6M HNO3 ; 5 minutes

Question 3

Centrifuge and decant the supernatant solution from ___

Answer 3

from procedure 3.

Question 4

Discard the
precipitates. To each of the ___, add _____. Allow the mixtures to cool and ____-

Answer 4

supernatant liquid ; 6 drops of 6M H2SO4 ; 5 drops of DI water.

Question 5

To the mixtures in _____- , add few drops of concentrated ____ until the solution
becomes ___. Confirm using a litmus paper. Record your observation.

Answer 5

procedure 4 ; NH3 ; basic

Question 6

To the centrifuge tube containing ____ , centrifuge and decant the supernatant liquid.

Answer 6

Bi^3+

Question 6

To the precipitate, add a few drops of ______ . Record your observation.

Answer 6

freshly prepared sodium stannite reagent

Question 6

To the solutions containing ___, add ___ of ____ and place in a hot water bath until the precipitates dissolve.

Answer 6

Sb+3 and Sn+2
15 to 20 drops concentrated HCI

Question 7

Add _____ of ______ to each centrifuge tubes. To the solution containing ___, add _______ and ___________ and
warm in the water bath.

Answer 7

1 mL of Di water ; Sb+3 ; 8
drops of 1M oxalic acid ; 2 drops of freshly prepared thioacetamide solution

Question 8

9. To the solution containing Sn+2, add __

Answer 8

add 0.1 M of AgCl2.