Study the Shift in Equilibrium between [Co(H₂O)₆] ²⁺ and Cl⁻ ions

# Materials Required

• 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 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.
• 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.
• 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.
• 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 step 1 for test tubes B, C, D, E, respectively.
• Click on the cap of the Acetone bottle to open it.
• Drag and drop 1 ml of Acetone to test tube A.
• Show an alert “Handle Acetone with care since it is flammable."
• Shows colour of the solution inside test tube A as blue.
• Drag and drop 0.8 ml of Acetone to test tube B.
• Drag and drop 0.6 ml of Acetone to test tube C.
• Drag and drop 0.4 ml of Acetone to test tube D.
• Drag and drop 0.2 ml of Acetone to test tube E.
• Drag and drop 0.2 ml of water to test tube B.
• Shows colour of the solution in test tube B changes to pink.
• Drag and drop 0.4 ml of water to test tube C.
• Shows colour of the solution in test tube C changes to pink.
• Drag and drop 0.6 ml of water to test tube D.
• Shows colour of the solution in test tube D changes to pink.
• Drag and drop 0.8 ml of water to test tube E.
• Shows colour of the solution in test tube E changes to pink.
• Shows an inference “Addition of H2O results in the formation of Pink colour.”
• Shows next button and click on the 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.
• Show a solution of pink colour formed inside 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.
• Drag and drop 1.5 ml of water to test tube B.
• Drag and drop 1 ml of water to test tube C.
• Drag and drop 0.5 ml of water to test tube D.
• Drag and drop 0.5 ml of conc. HCl to test tube A.
• Show an alert “Use conc. HCl carefully.”
• Show solution in test tube A turns light blue colour.
• Drag and drop 1 ml of conc. HCl to test tube B.
• Show solution in test tube B turns light blue colour.
• Drag and drop 1.5 ml of conc. HCl to test tube C.
• Show solution in test tube C turns light blue colour.
• Drag and drop 2 ml of conc. HCl to test tube D.
• Show solution in test tube D turns light blue colour.
• Drag and drop 2.5 ml of conc. HCl to test tube E.
• Show solution in test tube E turns light blue colour.
• Show inference “Addition of HCl results in the colour change of solution to light blue.”

# 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.