Question

What is the concentration of the dilute acid produced from adding 200 mL of distilled water to 50 mL of HCl acid whose concentration is 0.2 M?

Answer 1

We have to know this:

Solution here = HCl (solute) + Water (solvent)

Solution 1)

Volume 1 (V1)= 50 mL

Concentration 1 (M1) = 0.2 M

We add 200 mL of water into Solution 1, so we will have a diluted solution which is Solution 2.

Solution 2)

Volume 2 (V2, be careful with the dilution) = 50 mL + 200 mL (added) = 250 mL

Concentration 2 (M2) = Need to be found

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The formula we use to calculate concentration 2 is:

V1 x M1 = V2 x M2, we clear M2 from here and we get to:

M2 = (V1 x M1) / V2 = (50 mL x 0.2 M) / 250 mL = 0.04 M

M2 = 0.04 M ( we can say that it is right because when we add water, concentration of the solution will decrease)

Answer: M2 = 0.04 M (mol/L)