# If 200 mL of a 2.50 M NaOH solution is diluted to 500 mL, what is the new concentration of NaOH?

Nov 2, 2016

The new concentration is $1.00 \cdot m o l \cdot {L}^{-} 1$.

#### Explanation:

$\text{Concentration}$ $=$ $\text{Moles of solute"/"Volume of solution}$

We use this relationship to get the initial number of moles, by taking the product,$\text{concentration"xx"volume}$, and then dividing this molar quantity by the new volume, which we get by simply adding the 2 given volumes.

And thus, $\frac{200 \times {10}^{-} 3 \cancel{L} \times 2.50 \cdot m o l \cdot {L}^{-} 1}{500 \times {10}^{-} 3 \cancel{L}}$

And we get an answer with units $m o l \cdot {L}^{-} 1$ as we require.