# What is the molarity of a solution made by dissolving 20.0 g of H_3PO_4 in 50.0 mL of solution?

$\text{Molarity}$ $=$ $\text{Moles of solute"/"Volume of solution}$
So $\text{concentration}$ $=$ $\frac{20.0 \cdot g}{98.08 \cdot g \cdot m o {l}^{-} 1} \times \frac{1}{50.0 \times {10}^{-} 3 L}$ $\cong$ $4 \cdot m o l \cdot {L}^{-} 1$ w.r.t. ${H}_{3} P {O}_{4}$.