Question

In a titration, it took 13.67 mL of 0.40 M NaOH to neutralize 10.00 mL of the HCl. What is the molarity of the acid (HCl)? Give your answer to 2 decimal places.

Answer 1

To find the molarity of the HCl solution, we calculate the moles of NaOH, which equals the moles of HCl in a 1:1 reaction, and then divide by the volume of the HCl solution. The molarity of the HCl solution is found to be 0.55 M.

Step-by-step explanation:

The calculation of the molarity of an HCl solution in a titration where 13.67 mL of 0.40 M NaOH is used to neutralize 10.00 mL of HCl is based on the neutralization reaction:

HCl + NaOH → NaCl + H2O

Since the reaction is 1:1, the moles of NaOH will equal the moles of HCl at the neutralization point. To find the moles of NaOH, we multiply the volume by the molarity:

Moles NaOH = 13.67 mL × 0.40 M = 5.468 mmol

This is also the moles of HCl, since the reaction is 1:1. To find the molarity of the HCl, we divide the moles of HCl by the volume of HCl solution in liters:

Molarity of HCl = Moles HCl / Volume HCl in L

Molarity of HCl = 5.468 mmol / 10.00 mL = 5.468 mmol / 0.010 L = 0.5468 M

Thus, the molarity of the HCl solution is 0.55 M after rounding to two decimal places.