Question

A 67.0 mL aliquot of a 0.400 M stock solution must be diluted to 0.100 M. Assuming the volumes are additive, how much water should be added?

Answer 1

Answer:

201 mL of water should be added.

Calculation:

First we need to calculate the final volume of the diluted 0.100 M solution. Then we can substract the "initial volume of of 0.400 M stock solution" from the "final volume of the diluted 0.100 M solution".

Calculation of Final volume of the solution:

We can use the following formula,

This is the final volume of the diluted solution.

NV, = N₂V2 Where, N = initial concentreation = 0.400M (given) N2 = final concentreation = 0.100M (given) W, = initial volume = 67.0 mL (given) V2 = final volume = ? (we need to find out) Now, put these values in the above forenela 0.400M X 67.0 mL = 0.100 M X V₂ V = 0.400 M X 67.0mL 0.1004 V₂ = 268 mL

Now,

Calculation of amount of water added:

N2 = final volume of the solection = 268 mL Vi= initial volume of the solution & 67.0 mL Amount of water added = U₂ - V, Amount of water added = 268 mL - 67.0 mL Amount of water added = 201 mL)

So, 201 mL of water should be added to 67.0 mL aliquot of a 0.400 M stock solution to make 268 mL of 0.100 M solution.