Question

If the molar ratio was 1:1 between the acid and base and the acid is 10 mL and the base is 8.3 mL, how do you find the molar concentration of the acid when only given this information?

Answer 1

If you want the concentration of the acid in moles/L, you can't. If you want it in terms of the ratio and the molarity of the base it is the following:
mLacid x Macid = mLbase x Mbase
10 x Macid = 8.3 x Mbase
Macid = M base x 8.3/10 = 0.83*Mbase