Question

if 250 g of sodium hypochlorite is dissolved in 5 dm3 of water to prepare a solution. calculate the concentration in moles/dm3 of the sodium hypochlorite solution

Answer 1

Given:

250 g of sodium hypochlorite is dissolved in 5 dm3 of water to prepare a solution.

To find:

Concentration of the solution in moles/dm³ unit ?

Calculation:

Molecular Formula of Sodium Hypochlorite is NaClO , its molar mass is (23 + 35.5 + 16) = 74.5 g/mol.

Moles of Sodium hypochlorite :

$\rm \therefore \: no. \: of \: moles = \dfrac{given \: mass}{molar \: mass}$

$\rm \implies\: no. \: of \: moles = \dfrac{250}{74.5}$

$\rm \implies\: no. \: of \: moles = 3.35$

Now , concentration :

$\therefore \rm [NaClO] = \dfrac{moles}{volume}$

$\implies \rm [NaClO] = \dfrac{3.35}{5}$

$\implies \rm [NaClO] = 0.67 \: mol/ {dm}^{3}$

So, concentration of NaClO is 0.67 mol/dm³.