Question

35.0 mL of stock hydrochloric acid solution is added to a 500 mL volumetric flask. A student adds distilled water up to the line. Using a pH meter and logarithms, he finds the molarity of the new solution to be 0.062 M HCl. What is the molarity of the stock solution?

Answer 1

Molarity of stock HCl solution is 0.89 M

Step-by-step explanation:

The given problem can be solved using laws of dilution.

According to laws of dilution-
`C_(1)V_(1)=C_(2)V_(2)`

Where,
`C_(1)` and
`C_(2)` are initial and final concentration of a solution

`V_(1)` and
`V_(2)` are initial and final volume of a solution

Here,
`V_(1)=35.0mL`,
`C_(2)=0.062M` and
`V_(2)=500mL`

So,
`C_(1)=(C_(2)V_(2))/(V_(1))` =
`((0.062M)* (500mL))/(35.0mL)` = 0.89 M

Hence, molarity of stock HCl solution is 0.89 M