Question

g 10.00 mL of phosphoric acid (H3PO4) are titrated with 0.1000 M sodium hydroxide. 15.00 mL of the sodium hydroxide solution are used in this experiment. Determine the molarity of phosphoric acid.

Answer 1

Answer: The molarity of phosphoric acid is 0.05 M

Explanation:

A neutralization reaction is defined as the reaction in which an acid reacts with a base to form a salt and water molecule.

At equivalence, moles of acid becomes equal to the moles of base. The equation for the neutralization follows:

$n_1M_1V_1=n_2M_2V_2$              ........(1)

where,

$n_1, M_1\text{ and }V_1$ are the n-factor, molarity and volume of acid that is $H_3PO_4$

$n_2, M_2\text{ and }V_2$ are the n-factor, molarity and volume of the base that is NaOH

Given values:

$n_1=3\\M_1=?M\\V_1=10.00mL\\n_2=1\\M_2=0.1000M\\V_2=15.00mL$

Plugging values in equation 1:

$3\times M_1\times 10.00=1\times 0.1000\times 15.00\\\\M_1=\frac{1\times 0.1000\times 15.00}{3\times 10.00}\\\\M_1=0.05M$

Hence, the molarity of phosphoric acid is 0.05 M