Question

The flask contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.290 M NaOH. It requires 13.2 mL of the NaOH solution to reach the end point of the titration. A buret filled with a titrant is held above a graduated cylinder containing an analyte solution. What is the initial concentration of HCl

Answer 1

Answer:

0.383M

Explanation:

The following data were obtained from the question:

Volume of acid, HCl (Va) = 10mL

Molarity of acid, HCl (Ma) =...?

Molarity of base, NaOH (Mb) = 0.290 M

Volume of base, NaOH (Vb) = 13.2mL

Next, we shall write the balanced equation for the reaction. This is given below:

HCl + NaOH —> NaCl + H2O

From the balanced equation above,

The mole ratio of the acid (nA) = 1

The mole ratio of the base (nB) = 1

Finally, we shall determine the concentration of the acid, HCl solution as follow:

MaVa/MbVb = nA/nB

Ma x 10 / 0.29 x 13.2 = 1

Cross multiply

Ma x 10 = 0.29 x 13.2 x 1

Divide both side by 10

Ma = (0.29 x 13.2 x 1) /10

Ma = 0.383M

Therefore, the concentration of the acid, HCl is 0.383M.