Question

If 1.1g of nitrobenzene are added to 10.0 g of naphthalene, show the correct work to find the molality of the solution? (given: molar mass of nitrobenzene = 123.06g/mole)

Answer 1

Answer: Molality of solution is 0.89 mole/kg

Explanation:

Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.

$Molarity=\frac{n}{W_s}$

where,

n = moles of solute

$W_s$ = weight of solvent in kg

moles of nitrobenzene (solute) =$\frac{\text {given mass}}{\text {Molar Mas}}=\frac{1.1}{123.06g/mol}=0.0089$

mass of napthalene (solvent )= 10.0 g = 0.0100 kg

Now put all the given values in the formula of molality, we get

$Molality=\frac{0.0089}{0.0100kg}=0.89mole/kg$

Therefore, the molality of solution is 0.89 mole/kg