A 25.0 mL sample of an HCl solution is titrated with a 0.139 M NaOH solution. The equivalence point is reached with 25.3 mL of base. The concentration of HCl is __________ M.
A)11.7
B)0.00352
C)0.141
D)0.0352
E)0.139

Question

Quizplus · Accepted Answer

At the equivalence point, the moles of acid will be equal to the moles of base. Therefore, we can use the following equation to calculate the concentration of the acid:

Macid x Vacid = Mbase x Vbase

where Macid is the concentration of the acid, Vacid is the volume of the acid (in liters), Mbase is the concentration of the base, and Vbase is the volume of the base (in liters). Plugging in the given values, we get:

Macid x 0.0250 L = (0.139 M) x 0.0253 L

Solving for Macid, we get:

Macid = (0.139 M x 0.0253 L) / 0.0250 L

Macid = 0.141 M

Therefore, the concentration of HCl is 0.141 M. Answer choice C is the only option that matches this value.

A 250 ML Sample of an HCl Solution Is Titrated with with a 0.139