Answer:
0.07 M
Step-by-step 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