# What is the molarity of a solution made of 2.5 moles of KNO_3 in 5 L of water?

$\text{Molarity}$ $=$ $0.50$ $m o l \cdot {L}^{-} 1$
$\text{Molarity}$ $=$ $\left(\text{Moles of solute")/("Volume of solution (L)}\right)$
$=$ $\frac{2.50 \cdot m o l}{5 \cdot L}$ $=$ $0.50$ $m o l \cdot {L}^{-} 1$.
The volume of the solution formed when such a quantity of potassium nitrate is dissolved in $5$ $L$ of solvent would remain at $5$ $L$, or so close that the difference is negligible.