Question

A chemist must prepare 550 mL of hydrochloric acid solution with a pH of 1.60 at 25°C .

Answer 1

Answer: The volume of concentrated hydrochloric acid solution is 1.73 mL

Explanation:

To calculate the hydrogen ion concentration of the solution, we use the equation:

$pH=-\log[H^+]$

We are given:

pH = 1.60

Putting values in above equation, we get:

$1.60=-\log [H^+]$

$[H^+]=10^{-1.60}=0.0251M$

To calculate the volume of the concentrated solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated HCl solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted HCl solution

We are given:

$M_1=8.0M\\V_1=?mL\\M_2=0.0251M\\V_2=550mL$

Putting values in above equation, we get:

$8.0\times V_1=0.0251\times 550.0\\\\V_1=\frac{0.0251\times 550}{8.0}=1.73mL$

Hence, the volume of concentrated hydrochloric acid solution is 1.73 mL