A titration of 15.75mL HCL of an unknown molarity requires 20.35mL of 0.0903M NaOH solution. What is the molarity of the HCl solution?

Answer 1

HCl + NaOH ==> NaCl + H2O
mols NaOH = M x L = ?
Using the coefficients in the balanced equation, convert mols NaOH to mols HCl. You can see the ratio is 1 mol HCl to 1 mol NaOH; therefore, mols HCl = mols NaOH.
Then M HCl = mols HCl/L HCl.

Answer 2

C1V1=C2V2 law can be applied because the ratio is 1:1