A150 ml sample of hydrochloric acid (hcl) completely reacted with 60.0 ml of a 0.100 m naoh solution. the equation for the reaction is given below. hcl + naoh mc011-1.jpg nacl + h2o. what was the original concentration of the hcl solution?

The balanced chemical reaction is expressed as:

HCl + NaOH ---> NaCl + H2O

We are given the amount and the concentration of the sodium hydroxide reactant. This will be the starting point for the calculations. 

0.100 mol NaOH/L solution (0.06 L solution) ( 1 mol HCl / 1 mol NaOH) = 0.006 mol HCl

Molarity = amount in moles / Volume of solution = 0.006 mol HCl/ 0.150 L
Molarity = 0.04 M

A.(nh4)(2co3)is the correct answer