Question

A 5.00 mL aliquot of a 0.20 M HCl solution is diluted to a final volume of 25.00 mL. What is the molarity of this first dilution solution? Then a second dilution was made by taking 2.00 mL of the first dilution and diluting it to 50.00 mL.g What is the molarity of this second dilution?

Answer 1

Answer: The molarity of this second dilution is
`1.6* 10^(-3)`

Step-by-step explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

According to the neutralization law,

`M_1V_1=M_2V_2`

where,

`M_1` = molarity of stock solution = 0.20 M

`V_1` = volume of stock solution = 5.00 ml

`M_2` = molarity of dilute solution = ?

`V_2` = volume of dilute solution = 25.00 ml

`0.20* 5.00=M_2* 25.00`

`M_2=0.04`

The molarity of this first dilution solution is 0.04 M

`M_1V_1=M_2V_2`

where,

`M_1` = molarity of stock solution = 0.04 M

`V_1` = volume of stock solution = 2.00 ml

`M_2` = molarity of dilute solution = ?

`V_2` = volume of dilute solution = 50.00 ml

`0.04* 2.00=M_2* 50.00`

`M_2=1.6* 10^(-3)`

The molarity of this second dilution is
`1.6* 10^(-3)M`