Answer is: the molarity of HCl found in a titration is 0.1 M.
Balanced chemical reaction between hydrochloric acid and sodium hydroxide:
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l).
From balanced chemical reaction: n(HCl) : n(NaOH) = 1 : 1.
n(HCl) = n(NaOH).
c(HCl) · V(HCl) = c(NaOH) · V(NaOH).
c(HCl) = c(NaOH) · V(NaOH) ÷ V(HCl).
c(HCl) = 0.1 M · 50 ml ÷ 50 ml.
c(HCl) = 0.1 M; molarity of hydrochloric acid.
