Answer:
0.017 M
Explanation:
The balanced equation for the reaction is given below:
2H₃PO₄ + 3Ba(OH)₂ ⇌ Ba₃(PO₄)₂ + 6H₂O
From the balanced equation above,
The mole ratio of acid, H₃PO₄ (nₐ) = 2
The mole ratio of base, Ba(OH)₂ (n₆) = 3
Finally, we shall determine the concentration of the phosphoric acid, H₃PO₄. This can be obtained as follow:
Volume of acid, H₃PO₄ (Vₐ) = 125 mL
Volume of base, Ba(OH)₂ (V₆) = 63.7 mL
Concentration of base, Ba(OH)₂ (C₆) = 0.050M
Concentration of acid, H₃PO₄ (Cₐ) =?
CₐVₐ / C₆V₆ = nₐ/n₆
Cₐ × 125 / 0.05 × 63.7 = 2/3
Cₐ × 125 / 3.185 = 2/3
Cross multiply
Cₐ × 125 × 3 = 3.185 × 2
Cₐ × 375 = 6.37
Divide both side by 375
Cₐ = 6.37 / 375
Cₐ = 0.017 M
Thus, the concentration of the phosphoric acid, H₃PO₄ is 0.017 M
