A 150 mL sample of hydrochloric acid (HCl) completely reacted with 60.0 mL of a 0.100 M NaOH solution. The equation for the reaction is given below. HCl + NaOH Right arrow. NaCl + H2O What was the original concentration of the HCl solution? 0.040 M 0.25 M 1.50 M 2.50 M

0.040M

Explanation:

The following data were obtained from the question:

Volume of acid (Va) = 150mL

Volume of base (Vb) = 60mL

Molarity of base (Mb) = 0.1M

Molarity of acid (Ma) = ... ?

Next, 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 as follow:

MaVa / MbVb = nA/nB

Ma x 150 / 0.1 x 60 = 1/1

Cross multiply to express in linear form

Ma x 150 = 0.1 x 60

Divide both side by 150

Ma = 0.1 x 60 / 150

Ma = 0.04M

Therefore, the concentration of the acid is 0.04M