During a titration, 50.0 ml of 0.2M NaOH were required to neutralize 50.0ml of H3PO4. What's the concentration of the H3PO4 solution? Question 9 options: A) 0.07M B) 1.8M C) 0.6M D) 0.2M

0.07 M

Explanation:

Given data:

Volume of NaOH = 50.0 mL

Molarity of NaOH = 0.2 M

Volume of H₃PO₄ =  50.0 mL

Concentration of H₃PO₄ = ?

Solution:

3NaOH + H₃PO₄    →   Na₃PO₄  +  3H₂O

Number of moles of NaOH react:

Molarity = number of moles / volume in L

0.2 M = number of moles = 0.05 L

Number of moles = 0.01 mol

Now we will compare the moles of NaOH  with  H₃PO₄ .

          NaOH        :       H₃PO₄

             3             :          1

           0.01          :       1/3×0.01 = 0.0033

Concentration of H₃PO₄:

Molarity = number of moles / volume in L

Molarity = 0.0033 mol / 0.05 L

Molarity = 0.07 M