J.R. S. answered 10/03/19
Ph.D. University Professor with 10+ years Tutoring Experience
Balanced equation for the reaction taking place:
HCl + NaOH ===> NaCl + H2O
You can use V1M1 = V2M2 in which case you have...
(x ml NaOH)(0.120 M) = (14.00 ml HCl)(0.500 M HCl)
x = 58.33 mls of NaOH = 58.3 mls (to 3 sig. figs.)
You could also find moles of HCl present and equate that to volume of NaOH:
moles HCl = 0.01400 L x 0.500 mol/L = 0.007 moles HCl
moles NaOH needed = 0.007 moles HCl x 1 mol NaOH/mole HCl = 0.007 moles NaOH
Volume NaOH = (x L)(0.120 mol/L) = 0.007 moles and x = 0.583 L = 58.3 mls (to 3 sig. figs.)