# What is the osmolarity of 0.5*mol*L^-1 solution of magnesium sulfate?

Aug 11, 2017

The $\text{osmolarity}$ of $0.5 \cdot m o l \cdot {L}^{-} 1$ $M g S {O}_{4}$ is $1.0 \cdot m o l \cdot {L}^{-} 1$....

#### Explanation:

$\text{Osmolarity}$ is the concentration of a solution expressed as the total number of $\text{solute particles}$ per litre.....

In aqueous solution, magnesium sulfate speciates to give two moles of ions.......i.e.

$M g S {O}_{4} \stackrel{{H}_{2} O}{\rightarrow} M {g}^{2 +} + S {O}_{4}^{2 -}$

Charge and mass are balanced as is absolutely required.

And since magnesium sulfate gives rise to TWO EQUIVS of soluble ions, the osmolarity is equal to TWICE the molarity of $N {a}_{2} S {O}_{4}$. What is the osmolarity of $0.5 \cdot m o l \cdot {L}^{-} 1$ $A l {\left(N {O}_{3}\right)}_{3}$.....?