chemistry
posted by Monique .
a 10.0mL sample of an unknown H3PO4 solution requirs 112mL of 0.100 M KOH to completely react with the H3PO4. What was the concentrartion of the unknown H3PO4 solution?
H3PO4 + 3KOH > 3H2O + K3PO4
Ive seen these problems with one volume but not two volumes Im lost please help me with this problem

That's not a big complication.
moles KOH = M x L = ?
Convert moles KOH to moles H3PO4 with the coefficients in the balanced equation.
M H3PO4 = moles H3PO4/L H3PO4.
done. 
DrBob222 I think Im doing something wrong. When I worked this problem out I came up with the right answer but wrong units.
0.112L KOH x 0.100molKOH/LKOH x 1mol H3PO4/3 mol KOH x 0.01 L H3PO4/1 mol H3PO4 = 0.373 L H3PO4