Question

A chemist needs to know the concentration of some NaOH that is in the laboratory. To find this out, she titrates a 50.0 mL sample of the solution with 3.5 M HCl. If it takes 34.3 mL of the HCl to reach the titration endpoint, what is the concentration of the NaOH solution?

Answer 1

Answer: 2.4 M

Explanation:

According to the neutralization law,

$n_1M_1V_1=n_2M_2V_2$

where,

$M_1$ = molarity of $Hl$ solution = 3.5 M

$V_1$ = volume of $HCl$ solution = 34.3 ml

$M_2$ = molarity of $NaOH$ solution = ?

$V_2$ = volume of $NaOH$ solution = 50 ml

$n_1$ = valency of $HCl$ = 1

$n_2$ = valency of $NaOH$ = 1

$1\times 3.5M\times 34.3=1\times M_2\times 50$

$M_2=2.4$

Therefore, the concentration of NaOH solution is 2.4 M.