Question

You have a 50mL of a stock solution. How much water and stock should be mixed together to make a 1:10 dilution of working solution for a total of 100mL of solution

Answer 1

The final solution is 10 fold dilute to the original solution. Let the concentration of the stock solution is x.

So concentration of the final solution is x/10 or 0.1x

Use the following equation for dilution: V₁S₁ = V₂S₂

where, V₁ = volume of the original solution taken (to be determined)

S₁ = concentration of the original solution = x

V₂ = volume of the final solution = 100 mL

S₂ = concentration of the final solution = 0.1x

so, V₁ * x = (100 mL) * 0.1x

or, V₁ = 10 mL

So 10 mL of the stock solution and 90 mL of water should be mixed to get the 10 fold dilute solution.