Question

You are given a 1.00 molal solution of an unknown solute dissolved in water and told that you must determine if the solute is a strong electrolyte, a weak electrolyte, or a nonelectrolyte. On testing, you find that the freezing point of the solution is -2.05 degrees Celsius. Is this enough information to answer the question? The molal freezing point depression constant for water is 1.86 °C/m. O No, this is not enough information O Yes, the solute is a nonelectrolyte Yes, the solute is a weak electrolyte Yes, the solute is a strong electrolyte

Answer 1

Answer: Yes, the solute is a weak electrolyte

Explanation:

Depression in freezing point is given by:

$\Delta T_f=i\times K_f\times m$

$\Delta T_f=T_f^0-T_f=(0-(-2.05))^0C=2.05^0C$ = Depression in freezing point

i= vant hoff factor = ?

$K_f$ = freezing point constant = $1.86^0C/m$

m= molality

$\Delta T_f=i\times K_f\times m$

$2.05=i\times 1.86\times 1$

$i=1.10$

As i for non electrolytes is 1, the given compound must be an electrolyte and a weak electrolyte as the value is only slightly greater than 1.