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List the following aqueous solutions in order of increasing boiling point: 0.12 m C6H12O6, 0.05 m LiBr, and 0.05 m Zn(NO3)2. Explain your order.List the following aqueous solutions in order of increasing boiling point: 0.12 m C6H12O6, 0.05 m LiBr, and 0.05 m Zn(NO3)2. Explain your order.

Respuesta :

Answer: The order of increasing boiling points follows:

[tex]\text{LiBr }<C_6H_{12}O_6<Zn(NO_3)_2[/tex]

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:  0.12 m [tex]C_6H_{12}O_6[/tex]

Value of i = 1   (for non-electrolytes)

So, molal concentration will be = [tex](0.12)\times 1=0.12m[/tex]

  • Option 2:  0.02 m LiBr

Value of i = 2

So, molal concentration will be = [tex](0.02)\times 2=0.04m[/tex]

  • Option 3:  0.05 m [tex]Zn(NO_3)_2[/tex]

Value of i = 3

So, molal concentration will be = [tex](0.05)\times 3=0.15m[/tex]

As, the molal concentration of [tex]Zn(NO_3)_2[/tex] is the highest, so its boiling point will be the highest.

Hence, the order of increasing boiling points follows:

[tex]\text{LiBr }<C_6H_{12}O_6<Zn(NO_3)_2[/tex]