Question

What is the molarity of an HCl solution, if 28.6 ml of a 0.175 M of NaOH solution is needed to neutralize a 25.0 ml sample of the HCl solution

Answer 1

To find the molarity of an HCl solution that is neutralized by a known volume and molarity of NaOH, calculate the moles of NaOH used and then use the 1:1 reaction ratio to find the moles of HCl, which can be divided by the volume of HCl to find its molarity.

Step-by-step explanation:

To determine the molarity of an HCl solution when 28.6 mL of a 0.175 M NaOH solution is required to neutralize a 25.0 mL sample of HCl, we can use the concept of titration and the stoichiometry of the neutralization reaction between HCl and NaOH:

HCl + NaOH → NaCl + H₂O

First, we calculate the number of moles of NaOH used:

# moles NaOH = volume (L) × molarity (M)

# moles NaOH = 0.0286 L × 0.175 M

Since the reaction between HCl and NaOH is 1:1, the number of moles of HCl is equal to the number of moles of NaOH. We then calculate the molarity of HCl:

Molarity of HCl = # moles HCl / volume of HCl (L)

The molarity of the HCl solution is equal to the number of moles of NaOH divided by the volume of the HCl solution in liters (0.025 L).