Question

Arrange the following aqueous solutions in order of increasing boiling points 0.050 m Mg(NO3): 0.100 m ethanol 0.090 m NaCl Ethanol

Answer 1

Answer: The order of increasing boiling points follows:

`\text{Ethanol }<Mg(NO_3)_2<\text{ NaCl}`

Step-by-step explanation:

The expression of elevation in boiling point is given as:

`\Delta T_b=i* k_b* m`

where,

`\Delta T_b` = Elevation in boiling point

i = Van't Hoff factor

`T_b` = change in boiling point

`k_b` = boiling point constant

m = molality

For the given options:

• Option 1: 0.050 m
  `Mg(NO_3)_2`

Value of i = 3

So, molal concentration will be =
`(0.05)* 3=0.15m`

• Option 2: 0.100 m ethanol

Value of i = 1 (for non-electrolytes)

So, molal concentration will be =
`(0.100)* 1=0.100m`

• Option 3: 0.090 m NaCl

Value of i = 2

So, molal concentration will be =
`(0.09)* 2=0.18m`

As, the molal concentration of NaCl is the highest, so its boiling point will be the highest.

Thus, the order of increasing boiling points follows:

`\text{Ethanol }<Mg(NO_3)_2<\text{ NaCl}`