# How to figure out which substance has the highest osmotic pressure? [closed]

In preparing for an exam and I'm trying to solve the following question. I'm clueless. What should I do?

Which of the following water solutions has the highest osmotic pressure?

\begin{align} \tag1 \pu{0.1 mol/kg} &~ \ce{NaCl}\\ \tag2 \pu{0.1 mol/kg} &~ \ce{KF}\\ \tag3 \pu{0.1 mol/kg} &~ \text{sucrose}\\ \tag4 \pu{0.1 mol/kg} &~ \ce{MgCl2} \end{align}

$$\ce{MgCl2}$$ has the highest osmotic pressure because it breaks up into three ions in water, as opposed to all the others, which only break up into two.