Question

Calculate the molality of a saline solution in which 50.0 g of NaCl is dissolved in 0.750 kg of water.

Answer 1

Answer: Molality of a saline solution = 1.14 moles per kg

Step-by-step explanation:

Given mass of NaCl (m)= 50.0 g

Mass of solvent = 0.750 kg

Molar mass of NaCl (M)= 23 g + 35.5 g = 58.5g [Atomic mass of Na = 23 u , atomic mass of Cl = 35.5 u]

Number of moles (n) =
`(m)/(M)`

`(50)/(58.5)=.8547`

Molality =
`\frac{\text{Number of moles }}{\text{Mass of solvent in kg}}`

Hence, molality of a saline solution = 1.14 moles per kg