# Difference between the specific heat capacity of potassium chloride solution and sodium chloride solution

I am curious about the difference between the specific heat capacity of a potassium chloride solution (KCl + water) and a sodium chloride solution (NaCl + water) - particularly the specific heat capacity of which one is greater and by how much (a number would be nice!). You may assume that all variables for the two solutions are the same - volume, concentration, etc.

I assume that this would have to be linked to ionic bonding to understand which molecules are affected by heating the solution but I am not aware of the differences in bonding in the two solutions, and more importantly, how to represent it mathematically.

A simple one-liner such as "Solution X has a greater specific heat capacity than Solution Y by a factor of n" would be perfect (some reasoning/explanation would be great as well).

The Handbook of Chemistry and Physics gives the following heat capacities for $$\ce{KCl}$$ and $$\ce{NaCl}$$ solutions at $$\pu{18°C}$$ :

Mole fraction x 0.04 0.02 0.01
$$\ce{KCl}$$ 3.46 $$\pu{J g^{-1} K^{-1}}$$ 3.78 $$\pu{J g^{-1} K^{-1}}$$ 3.966 $$\pu{J g^{-1} K^{-1}}$$
$$\ce{NaCl}$$ 3.68 $$\pu{J g^{-1} K^{-1}}$$ 3.895 $$\pu{J g^{-1} K^{-1}}$$ 4.025 $$\pu{J g^{-1} K^{-1}}$$
• Would you know how to find the (approximate) value of any mole fraction and at any temperature using this table?
– user121821
Mar 9 at 8:25