Question

Determine the concentration of a phosphoric acid solution if a 25.00 mL sample of phosphoric acid of unknown concentration requires 35.77 mL of a 0.250 M NaOH solution to reach the equivalence point.

Answer 1

Answer: The concentration of given phosphoric acid solution is 0.357 M.

Explanation:

Given: $V_{1}$ = 25.00 mL,    $M_{1} = ?$

$V_{2}$ = 35.77 mL,            $M_{2}$ = 0.250 M

Formula used to calculate the concentration of phosphoric acid is as follows.

$M_{1}V_{1} = M_{2}V_{2}$

Substitute the values into above formula as follows.

$M_{1}V_{1} = M_{2}V_{2}\\M_{1} \times 25.00 mL = 0.250 M \times 35.77 mL\\M_{1} = 0.357 M$

Thus, we can conclude that concentration of given phosphoric acid solution is 0.357 M.