Question

If, by accident, you had added the phenolphthalein to the NaOH instead of the HCL could you have still carried out the titration? If so, how would you know when you reached the endpoint?

Answer 1

Solution :-

Even if we add phenolphthalein accidentally to the NaOH solution instead of the HCl solution then also we can carry out the titration.

After the adding phenolphthalein to the NaOH solution the color of the solution become dark pink

And when we titrate this NaOH solution with HCl solution then at the neutralization point the color of solution will disappear because phenolphthalein gives pink color in the basic solution and it becomes colorless in acidic solution.

Therefore when we titrate NaOH solution with HCl solution then color of the NaOH solution will disappear slowly and at the end point it becomes colorless.

So the end point of this titration will be dark pink to colorless.

This way we can carry out this titration.