Answer: The correct option is A) 0.068 m
Explanation:
Molality is defined as the amount of solute expressed in the number of moles present per kilogram of solvent. The units of molarity are mol/kg. The formula used to calculate molarity:
[tex]\text{Molality of solution}=\frac{\text{Given mass of solute}}{\text{Molar mass of solute}\times \text{Mass of solvent (in kg)}}[/tex] .....(1)
We are given:
Given mass of NaCl = 120 g
Molar mass of NaCl = 58.45 g/mol
Mass of solvent = 30 kg
Putting values in equation 1, we get:
[tex]\text{Molality of NaCl}=\frac{120}{58.44\times 30}\\\\\text{Molality of NaCl}=0.068m[/tex]
Hence, the correct option is A) 0.068 m
