Answer to Question #348471 in General Chemistry for thick headed

Question

In a titration experiment, an average of 15.2 mL of a 0.25 mol/L NaOH solution was needed to neutralize 20.0 mL of an unknown concentration of HCl. What is the molar concentration of the HCl solution?

Answer 1

1.

We can find the amount of NaOH by the following formula:

n = C_M * V

n(NaOH) = 0,25mol/l * 0,0152 l = 0,0038mol

2.

We find the amount of HCl.

NaOH + HCl = NaCl + H₂O

1mol NaOH — 1mol HCl

0,0038mol NaOH — X

X = 0,0038 mol HCl

3.

We find the concentration of HCl by the following formula:

$C_M= \cfrac {n} {V}= \cfrac {0,0038}{0,02}= 0,19mol/l$

Answer: 0,19 mol/l