what volume of 0.100 M NaOH will react completely with 28.00 mL of 0.550 M HCl?
Write the equation.
HCl + NaOH ==> NaCl + H2O.
mols HCl = L x M = 0.028 L x 0.550 M = ??
mols HCl = mols NaOH
mols NaOH = L x M. You know mols, you know M, solve for L. Post yuor work if you get stuck.