Question

50.00 mL of unknown calcium hydroxide solution is titrated with 0.250 M standard nitric acid solution. If 43.43 mL of the standard acid solution is required to reach a phenolphthalein endpoint, what is the molarity of the unknown calcium hydroxide solution

Answer 1

Answer: Molarity of the unknown calcium hydroxide solution is 0.217 M.

Explanation:

Given: $V_{1}$ = 50.00 mL,     $M_{1}$ = ?

$V_{2}$ = 43.43 mL,         $M_{2}$ = 0.250 M

Formula used is as follows.

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

Substitute the values into above formula as follows.

$M_{1}V_{1} = M_{2}V_{2}\\M_{1} \times 50.00 mL = 0.250 M \times 43.43 mL\\M_{1} = \frac{0.250 M \times 43.43 mL}{50.00 mL}\\= 0.217 M$

Thus, we can conclude that molarity of the unknown calcium hydroxide solution is 0.217 M.