Question

What would be the concentration of a solution made by diluting 45.0 mL of 4.2 M KOH to 250 mL?

Answer 1

As always, `"concentration"="Moles of solute"/"Volume of solution"..........`

Explanation:

And here (i) we calculate the `"moles of solute"` in the initial volume:

`=45xx10^-3Lxx4.2*mol*L^-1=0.189*mol` with respect to `KOH(aq)`.

And then (ii) we divide this value by the NEW volume of solution:

`"Concentration"=(0.189*mol)/(0.250*L)~=0.8*mol*L^-1` with respect to `KOH`.

The volume has increased approx. fivefold, and hence the concentration decreases approx. fivefold........