Respuesta :
Answer: The correct answer is Option b.
Explanation:
The expression of elevation in boiling point is given as:
[tex]\Delta T_b=i\times k_b\times m[/tex]
where,
[tex]\Delta T_b[/tex] = Elevation in boiling point
i = Van't Hoff factor
[tex]T_b[/tex] = change in boiling point
[tex]k_b[/tex] = boiling point constant
m = molality
For the given options:
Option 1: 0.100 m [tex]NaNO_3[/tex]
Value of i = 2
So, molal concentration will be = [tex](0.100)\times 2=0.200m[/tex]
Option 2: 0.100 m [tex]Li_2SO_4[/tex]
Value of i = 3
So, molal concentration will be = [tex](0.100)\times 3=0.300m[/tex]
Option 3: 0.200 m [tex]C_3H_8O_3[/tex]
Value of i = 1 (for non-electrolytes)
So, molal concentration will be = [tex](0.200)\times 1=0.200m[/tex]
Option 4: 0.060 m [tex]Na_3PO_4[/tex]
Value of i = 4
So, molal concentration will be = [tex](0.060)\times 4=0.24m[/tex]
As, the molal concentration of [tex]Li_2SO_4[/tex] is the highest, so its boiling point will be the highest.
Thus, the order of increasing boiling points follows:
[tex]NaNO_3=C_3H_8O_3<Na_3PO_4<Li_2SO_4[/tex]
Hence, the correct answer is Option b.
