Materials Required
- Conical flask (100 ml)
- Beaker
- Test tubes
- Test tube stand
- Measuring cylinders
- Distilled Water
- Acetone
- Concentrated hydrochloric acid: 30 mL
- Cobalt chloride solution (60mL of Acetone + 0.600 g of Cobalt chloride)
The Procedure
Real Lab Procedure
- Take 60 mL of acetone in a 100 mL conical flask and dissolve 0.6000 g CoCl2 in it to get a blue solution.
- Take 5 test-tubes labelled as A, B, C, D, and E.
- Add 3mL of cobalt chloride solution to each test tube.
- Add 1mL, 0.8mL, 0.6mL, 0.4mL and 0.2mL acetone to test tubes A, B, C, D and E respectively.
- Then add 0.2mL, 0.4mL, 0.6mL, 0.8mL of water to test tubes B, C, D and E, respectively, so that the total volume of solution in each of the test tubes is 4.0mL.
- Now compare the intensity of the colours in the test tubes B, C, D and E with the blue colour in test tube A taken as the reference test tube.
Experiment part: - 2
- Take 10 mL of Cobalt chloride solution in test tube X and add 5 mL distilled water to it, i.e., A solution of pink colour can be observed.
- Take 1.5mL of this solution in 5 different test tubes labelled as A, B, C, D and E.
- Add 2mL, 1.5mL, 1mL and 0.5mL of water to test tubes A, B, C and D.
- Add 0.5mL, 1mL, 1.5mL, 2mL and 2.5mL conc. HCl to test tubes A, B, C, D and E respectively, so that the total volume of solution in the test tubes is 4 mL.
- Now compare the intensity of the colours in the test tubes A, B, C, D and E with the pink colour in test tube X taken as the reference test tube.
Simulator Procedure
- Drag and drop 3ml of cobalt chloride solution to test tube A.
- Repeat the above step for test tubes B, C, D and E respectively.
- Click on the cap of the acetone bottle to open it.
- Drag and drop 1 ml of acetone to test tube A, 0.8 ml to B, 0.6 ml of to C, 0.4 ml of to D and 0.2 ml of acetone to test tube E.
- Drag and drop 0.2 ml of water to test tube B, 0.4 ml to C, 0.6 ml to D and 0.8 ml to E.
- Click on the Inference icon: “Addition of H2O in Cobalt chloride solution (60mL of Acetone + 0.600 g of Cobalt chloride) results in the formation of Pink colour.”
- Click on Next button
- Drag and drop 10 mL of cobalt chloride solution in test tube X.
- Drag and drop 5 mL distilled water to test tube X.
- Drag and drop the solution in test tube X to 5 different test tubes (1.5 ml each) labelled as A, B, C, D and E, respectively.
- Drag and drop 2 ml of water to test tube A, 1.5 ml to B, 1ml to C and 0.5 ml to D.
- Drag and drop 0.5 ml of conc. HCl to test tube A, 1 ml to B, 1.5 ml to C, 2 ml to D and 2.5 ml to E.
- Click on the Inference icon: “Addition of HCl results in the colour change of solution to light blue.”
- Click on the Reset button to redo the experiment.
Observation
- Colour change of solution from blue to pink with increasing amount of water.
- Colour change of solution from pink to light blue with increase in amount of HCl can be observed.
Observations are given in the table;
Test tube
|
Volume of Acetone added in mL
|
Volume of CoCl2 solution added in mL
|
Volume of water added in mL
|
Colour of solution
|
A
|
1.0
|
3.0
|
0.0
|
Blue
|
B
|
0.8
|
3.0
|
0.2
|
Pink
|
C
|
0.6
|
3.0
|
0.4
|
Pink
|
D
|
0.4
|
3.0
|
0.6
|
Pink
|
E
|
0.2
|
3.0
|
0.8
|
Pink
|
Table :- Study of equilibrium shift when adding water
Test tube
|
Volume of conc. HCl added in mL
|
Volume of aquo complex solution added in mL
|
Volume of water added in mL
|
Colour of solution
|
A
|
0.5
|
1.5
|
2.0
|
Light blue
|
B
|
1.0
|
1.5
|
1.5
|
Light blue
|
C
|
1.5
|
1.5
|
1.0
|
Light blue
|
D
|
2.0
|
1.5
|
0.5
|
Light blue
|
E
|
2.5
|
1.5
|
0.0
|
Light blue
|
Table :- Study of equilibrium shift when adding Cl– ions
Precaution
- Use conc. HCl carefully.
- Use only distilled water.
- Handle Acetone or alcohol with care, since it is flammable.