Question

Choose the aqueous solution that has the highest boiling point.These are all solutions of nonvolatile solutes and you shouldassume ideal van't Hoff factors where applicable.

a. 0.100 m NaNO3
b. 0.100m Li2SO4
c. 0.200m C3H8O3
d. 0.060m Na3PO4

Answer 1

Answer: The correct answer is Option b.

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: 0.100 m
`NaNO_3`

Value of i = 2

So, molal concentration will be =
`(0.100)* 2=0.200m`

Option 2: 0.100 m
`Li_2SO_4`

Value of i = 3

So, molal concentration will be =
`(0.100)* 3=0.300m`

Option 3: 0.200 m
`C_3H_8O_3`

Value of i = 1 (for non-electrolytes)

So, molal concentration will be =
`(0.200)* 1=0.200m`

Option 4: 0.060 m
`Na_3PO_4`

Value of i = 4

So, molal concentration will be =
`(0.060)* 4=0.24m`

As, the molal concentration of
`Li_2SO_4` is the highest, so its boiling point will be the highest.

Thus, the order of increasing boiling points follows:

`NaNO_3=C_3H_8O_3<Na_3PO_4<Li_2SO_4`

Hence, the correct answer is Option b.