When a chemist titrates a standard solution of 168.61 ml of hydrochloric acid (hcl) with 0.104 m sodium hydroxide (naoh) , she finds that it requires 259.4 ml of the base to reach the endpoint of the titration. what is the molarity of the acid solution ?

The conc of NaOH is 0.104M which means that 1000mL solution contains 0.104mol of NaOH, so the amount of moles used in the titration will be

The reaction of NaOH and HCl is one to one so the moles of HCl that were titrated will also be 
The Molarity is therefore

Variables,control,conclusion and finally scientific theory