Question

15.90 kJ and 18.58kJ are the heats absorbed when one mole of KCl is dissolved in 20 moles of water and 200 moles of water
respectively. The heat of dilution of KCl is (in kJ)
(A) -2.68
(B) 2.68
(C) 34.48
(D) -34.48​

Answer 1

Given: 15.90 kJ and 18.58 kJ are the heats absorbed when one mole of KCl is dissolved in 20 moles of water and 200 moles of water.

To find:  The heat of dilution of KCl?

Solution:

• The heat of dilution, or enthalpy of dilution, refers to the enthalpy change associated with the dilution process of a component in a solution at a constant pressure.

• As we have given that heats are absorbed  when one mole of KCl is dissolved in 20 moles of water and 200 moles of water  respectively.

• So the formula for heat of dilution is :

              delta (H2) - delta (H1)

• So putting the heats absorbed value in the formula, we get:

             delta (H2) - delta (H1) = 18.58kJ - 15.90 kJ

             heat of dilution = 2.68 kJ.

Answer:

           So the heat of dilution is 2.68 kJ.