Question

A student completes a titration by adding 12.0 milimeters of NaOH(aq) of unknown concentration to 16.0 milimeters of 0.15 HCl(aq). What is the molar concentration of the NaOH(aq)?

Answer 1

the balanced equation for the above reaction is as follows
NaOH  + HCl ---> NaCl + H₂O
stoichiometry of NaOH to HCl is 1:1
number of HCl moles reacted - 0.15 mol/L x 0.0160 L = 0.0024 mol
therefore number of NaOH moles reacted - 0.0024 mol
there are 0.0024 mol of NaOH in 12.0 mL
therefore in 1000 L - 0.0024 mol / 12.0 mL x 1000 mL = 0.20 mol
molarity of NaOH is 0.20 M