Final answer:
Adding 3 ml of 1 M HCl to the solution will increase the concentration of hydronium ions, lower the pH, and potentially drive a reaction with any base present in the solution.
Step-by-step explanation:
If you add 3 ml of 1 M HCl to the solution in step 7, what will be the resulting effect or reaction? The addition of 3 ml of 1 M HCl will increase the concentration of H3O+ (hydronium ions) in the solution.
This increase in hydronium ions will result in a shift in chemical equilibrium according to Le Chatelier's principle, and will cause a reaction with any base that is present in the solution.
If the solution in step 7 contained a base or was at equilibrium, this addition of a strong acid would drive the equilibrium towards the formation of more water and the conjugate acid of the base, thereby lowering the pH of the solution and making it more acidic.