Question

A 25.00ml sample of an HCl solution is placed in a flask with a few drops of phenolphthalein indicator. If 32.60ml of a 0.185M NaOH solution is needed to reach the endpoint, what is the concentration of the HCl solution?

Answer 1

To find the concentration of the HCl solution, set up a proportion using the balanced equation HCl + NaOH → NaCl + H₂O and solve for x.

Step-by-step explanation:

In a titration, a 25.00 mL sample of an HCl solution is titrated with a 0.185 M NaOH solution using phenolphthalein as an indicator. The endpoint is reached when 32.60 mL of the NaOH solution is added. To find the concentration of the HCl solution, we can use the equation:

HCl + NaOH → NaCl + H₂O

We can set up a proportion using the balanced equation:

25.00 mL HCl / x M = 32.60 mL NaOH / 0.185 M

Solving for x, we find that the concentration of the HCl solution is 0.239 M.