Chemistry math help

Question

By titration, it is found that 28.7mL of 0.132 M NaOH(aq) is needed to neutralize 25.0 mL(aq) of  Calculate the concentration of the HCI solution.

Answer 1

NaOH + HCl ==> NaCl + H2O ... balanced equation

Since the mole ratio of NaOH to HCl is 1:1, you can use M1V1 = M2V2

(28.7 ml)(0.132 M) = (25.0 ml)(x M)

x = 0.152 M

Doing it another, longer way, we calculate moles of NaOH, convert to moles HCl and divide moles HCl by liters of HCl to get moles/lliter = M.

moles NaOH = 28.7 ml x 1 L/1000 ml x 0.132 mol/L = 0.00379 moles NaOH

moles HCl = 0.00389 moles NaOH x 1 mol HCl/mole NaOH = 0.00379 moles HCl

molarity of HCl = 0.00379 moles/0.025 L = 0.152 M