Question

example 4
what is the total molar concentration of ions in a 0.350 m solution of the strong electrolyte na₂so₄? assume complete dissociation.

Explanation:

Step1: Write dissociation equation

$$\ce{Na2SO4 -> 2Na+ + SO4^{2-}}$$

Step2: Calculate ion concentration

For every 1 mole of $\ce{Na2SO4}$, we get 2 moles of $\ce{Na+}$ and 1 mole of $\ce{SO4^{2-}}$.
The concentration of $\ce{Na+}$ is $2\times0.350\ M = 0.700\ M$.
The concentration of $\ce{SO4^{2-}}$ is $1\times0.350\ M = 0.350\ M$.

Step3: Calculate total ion concentration

Total molar concentration of ions = $[Na^+]+[SO_4^{2 - }]$
$$0.700\ M+ 0.350\ M=1.05\ M$$

Answer:

$1.05\ M$