Question

Calculate the molality of a 150% by mass solution of MgCl, FW-95.3 g/mol in H.O. The density of tis solution is 1.127 gim 0.0134 m 0.157 m 1.58 m 1.86 m 11.8 m igator Delete Backspace U 10 pilli

Answer 1

Answer: 1.86 m

Step-by-step explanation:

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

`Molality=(n* 1000)/(W_s)`

where,

n = moles of solute

`W_s` = weight of solvent in g

Given : 15.0 grams of
`MgCl_2` is present in 100 g of solution

Moles of solute
`H_2O=\frac{\text {given mass}}{\text {Molar mass}}=(15.0g)/(95.3g/mol)=0.16`

mass of solution = 100 g

density of solution = 1.127g/ml

mass of solvent = mass of solution - mass of solute = 100 g - 15.0g = 85.0 g

`Molality=(0.16* 1000)/(85.0g)=1.86`

Thus molality of a 15.0% by mass solution of
`MgCl_2` is 1.86m.