When chloride ions are added to a solution containing Co(H2O)6^2+(aq), the following equilibrium is established - HSC - SSCE Chemistry - Question 13 - 2011 - Paper 1
Question 13
When chloride ions are added to a solution containing Co(H2O)6^2+(aq), the following equilibrium is established.
Co(H2O)6^2+(aq) + 4Cl^-(aq) ⇌ CoCl4^2-(aq) + 6H2O(l... show full transcript
Worked Solution & Example Answer:When chloride ions are added to a solution containing Co(H2O)6^2+(aq), the following equilibrium is established - HSC - SSCE Chemistry - Question 13 - 2011 - Paper 1
Step 1
Diluting the solution with water will make it turn blue.
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Answer
This statement is incorrect. Diluting the solution generally does not shift the equilibrium significantly toward the blue-coloured CoCl4^2- compound, as the addition of water would not favor the chloride ions.
Step 2
If the reaction is exothermic, heating the solution will make it turn blue.
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Answer
This statement is also incorrect. For exothermic reactions, heating the solution shifts the equilibrium towards the reactants, which would keep the solution pink.
Step 3
If the reaction is endothermic, cooling the solution will make it turn pink.
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Answer
This statement is correct. In an endothermic reaction, cooling the solution will shift the equilibrium towards the pink-coloured reactant, Co(H2O)6^2+.
Step 4
Adding a large amount of solid potassium chloride to the solution will make it turn pink.
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Answer
This statement is incorrect. Adding potassium chloride increases the concentration of Cl^- ions, which shifts the equilibrium towards the production of CoCl4^2- and hence makes it turn blue.
