Question

What's V2 in general/how do you calculate it step by step?

This is the question: If I add 25 mL of water to 125 mL of a 0.15 M NaOH solution, what will the molarity of the diluted solution be?

Answer 1

Well volumes are generally additive, and of course the concentration will be diluted.

Explanation:

By one of the definitions, `"concentration"="Moles of solute"/"Volume of solution".`

And thus `"moles of solute"="concentration"xx"volume of solution"`

And so.....the new concentration will be given by the quotient....

`(125xx10^-3*cancelLxx0.15*mol*cancel(L^-1))/(125xx10^-3*L+ 25xx10^-3*L)`

`=0.125*mol*L^-1`, i.e. concentration has reduced slightly.

This goes back to the old equality, `C_1V_1=C_2V_2`, when a given concentration is diluted, the new concentration is readily accessible.

Here we solved for `C_2=(C_1V_1)/V_2`.........