Question

Solutions A and B contain the same compound dissolved in water. Solution A is 5.0L at 0.020M and solution B is 50.0 mL at 0.60M. How many liters of solution A are needed to contain the same number of moles as the 50.0 mL of solution B?

Answer 1

Answer: The volume of solution A required is 0.15 L

Explanation:

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$        .......(1)

• For Solution B:

Molarity of solution B = 0.60 M

Volume of solution B = 50.0 mL  = 0.050 L    (Conversion factor: 1 L = 1000 mL)

Putting values in equation 1, we get:

$0.60M=\frac{\text{Moles of solution B}}{0.050L}\\\\\text{Moles of solution B}=(0.60mol/L\times 0.050L)=0.003mol$

Now, calculating the volume of solution A required for the same number of moles as solution B.

Moles of solution A = 0.003 moles

Molarity of solution A = 0.020 M

Putting values in equation 1, we get:

$0.020M=\frac{0.003mol}{\text{Volume of solution A}}\\\\\text{Volume of solution A}=\frac{0.003}{0.02}=0.15L$

Hence, the volume of solution A required is 0.15 L