Question

Calcium chloride, when dissolved in water, dissociates into its ions according to the following equation :
$CaC{l}_{2\left(aq\right)}\to C{a}_{aq}^{2+}+2C{l}_{aq}^{-}$

Calculate the number of ions obtained from $CaC{l}_2$ when 222 g of its dissolved in water.

Answer 1

$1$ mole→ 111 g $CaC{l}_2$
$\therefore$ $222gCaC{l}_2$ is equivalent to $2$ moles of $CaC{l}_2$
Since $1$ formula unit $CaC{l}_2$ gives $3$ ions, therefore, $1$ mol of $CaC{l}_2$
will give $3$ moles of ions
$2$ moles of $CaC{l}_2$ would give $3\times 2=6$ moles of ions.
No. of ions = No. of moles of ions $\times$ Avogadro number
$=6\times 6.022\times {10}^{23}$
$=36.132\times {10}^{23}$
$=3.6132\times {10}^{24}ions$