Chemical Reaction Stoichiometry: Calculating Original Concentration of HCl Solution

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.

Answer : The original concentration of HCl is 0.04 M

Explanation:

HCl + NaOH → NaCl + H2O

According to the neutralization law,

M1V1=M2V2

where,

M1 = molarity of NaOH solution = 0.100 M

V1 = volume of NaOH solution = 60.0 ml

M2 = molarity of HCl solution = ?

V2 = volume of HCl solution = 150 ml

Now put all the given values in the above law, we get the molarity of HCl solution.

(0.100M) × 60ml = (M2) × (150ml)

M2 = 0.04M

Therefore, the original concentration of HCl is 0.04 M