Question

A solution is prepared by dissolving 0.7234 g oxalic acid (H2C2O4) in enough water to make 100.0 mL of solution. A 10.00-mL aliquot (portion) of this solution is then diluted to a final volume of 250.0 mL. What is the final molarity of the diluted oxalic acid solution?

Answer 1

Answer: The final molarity of the diluted oxalic acid solution is 0.0032 M

Explanation:

Molarity: It is defined as the number of moles of solute present per liter of the solution.

Formula used :

$Molarity=\frac{n\times 1000}{V_s}$

where,

n= moles of solute

Moles=$\frac{\text{Given mass}}{\text{Molar mass}}=\frac{0.7234g}{90g/mol}=0.008moles$

$V_s$ = volume of solution in ml

$Molarity=\frac{0.008\times 1000}{100.0}=0.08$

To calculate the final molarity of the diluted oxalic acid solution

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of concentrated oxalic acid solution.

$M_2\text{ and }V_2$ are the molarity and volume of diluted oxalic acid solution.

We are given:

$M_1=0.08\\V_1=10.00mL\\M_2=?\\V_2=250.0mL$

Putting values in above equation, we get:

$0.08\times 10.00=M_2\times 250.0\\\\M_2=0.0032M$

Thus the final molarity of the diluted oxalic acid solution is 0.0032 M