Answer:
0.127 M.
Explanation:
The balanced equation for the reaction is given below:
H3PO4 + 3KOH —› K3PO4 + 3H2O
From the balanced equation above, we obtained the following data:
Mole ratio of acid, H3PO4 (nA) = 1
Mole ratio of base, KOH (nB) = 3
Data obtained from the question include:
Volume of acid, H3PO4 (Va) = 78.5 mL
Molarity of acid, H3PO4 (Ma) =...?
Volume of base, KOH (Vb) = 134 mL
Molarity of base, KOH (Mb) = 0.224 M
The concentration of the acid, H3PO4 can be obtained as follow:
MaVa / MbVb = nA/nB
Ma x 78.5 / 0.224 x 134 = 1/3
Cross multiply
Ma x 78.5 x 3 = 0.224 x 134 x 1
Divide both side by 78.5 x 3
Ma = (0.224 x 134 x 1) /(78.5 x 3)
Ma = 0.127 M
Therefore, the concentration of the acid, H3PO4 is 0.127 M.
