System:
Co(H2O)6^2+(aq) + 4Cl^-(aq) <==> CoCl4^2-(aq) + 6H2O(l)
Q: What would happen when you add HCl as a source of Cl- ions? Explain the observations in terms of Le Chatelier's principle.
Would the answer be that the reaction shifts to the right? How would you say this in 'terms of Le Chatelier's principle'.
Thanks
Yes, the reaction shifts to the right.
Because the reactant concentration increased, equilibrium will be shifted to product
In terms of LC principle you have disturbed the equilibrium by increasing the Cl- concentration. The system will therefore shift in such a way as to accommodate the change and to do this it needs to reduce the Cl- and does so by the cobalt complex reacting with the Cl- to produce more product.
[I am not a fan of writing the explanation in such a way as though it seems like the system makes a decision, but it is often written this way]
Thanks!
One more thing, could someone check these answers?
1) By adding H2O the equation shifts to the left
2) By adding AgNO3 the equation shifts to the left
3) By adding acetone the equation shifts to the right
When you add HCl as a source of Cl- ions to the system, it means that you are increasing the concentration of Cl- ions in the solution. According to Le Chatelier's principle, when a stress is applied to a system at equilibrium, the system will react in a way that minimizes the effect of that stress.
In this case, the stress is the increase in Cl- ion concentration. To minimize this stress, the reaction will shift in the direction that consumes the Cl- ions, which is towards the right side of the equation. This means that more CoCl4^2- ions will be formed, resulting in a deepening of the red color of the solution.
Therefore, when you add HCl as a source of Cl- ions, the reaction shifts to the right, which means more CoCl4^2- ions are produced. This observation is in line with Le Chatelier's principle, which states that a system at equilibrium will shift in a direction that counteracts the applied stress, in this case, to consume the excess Cl- ions.