Question

H₂PO₂ +3 NaOH →

0.08 M NaOH
(green)
Na PO + 3 H₂O
If 25.0 mL of H₂PO, 0.16 M are required to titrate 150.0 mL of NaOH to the equivalence point, what is the molarity
of the NaOH?
0.16 M NaOH
(sky blue)
0.02 M NaOH
(yellow)

Answer 1

The balanced chemical equation for the reaction between H₂PO₂ and NaOH is:

H₂PO₂ + 3 NaOH → Na₃PO₄ + 3 H₂O

Step-by-step explanation:

From the equation, we can see that 1 mole of H₂PO₂ reacts with 3 moles of NaOH to produce 1 mole of Na₃PO₄ and 3 moles of H₂O.

The volume of NaOH used in the titration is 150.0 mL, which is equivalent to 0.150 L. The molarity of the H₂PO₂ solution used is 0.16 M, which means that 0.16 moles of H₂PO₂ were used in the titration.

According to the balanced equation, 1 mole of H₂PO₂ reacts with 3 moles of NaOH. Therefore, the number of moles of NaOH used in the titration is three times the number of moles of H₂PO₂ used:

Number of moles of NaOH = 3 × 0.16 = 0.48 moles

The volume of NaOH used is 0.150 L, so the molarity of NaOH can be calculated as follows:

Molarity of NaOH = Number of moles of NaOH / Volume of NaOH used

Molarity of NaOH = 0.48 moles / 0.150 L

Molarity of NaOH = 3.2 M

Therefore, the molarity of NaOH is 3.2 M, which is represented by the sky blue color.