70 ION IS ATI ON 



temperature will affect salts according to the dissociation constant 

 of the acids and bases composing them, 



(a) Both strong, temperature of little effect. 



(b) Weak acid + strong base. Increase of temperature causes tlie degree 

 of dissociation of acid to increase. Anions combine with hydrogen ions 

 from HgO and liberate OH . 



(c) Strong acid and weak base. Increase of temperature causes the degree 

 of dissociation of base to increase. Base ions combine with hydroxyl ions 

 from the HgO and liberate H^. 



(d) Both weak. The result of any increase in temperature is to increase the 

 dissociation of the weaker at a greater rate than the stronger with correspond- 

 ingly slight changes in [H] and [OH]. 



It will be seen that apart from the action of temperature on the dissociation 

 of water itself, in {b) increased alkalinity and in (c) increased acidity result 

 from increase in temperature. This action is slight, however, compared to 

 the action of temperature on the weakest salt known, water. 



The effect of alterations of temperature on a salt solution where one of the 

 constituents of the salt is weak is the combined effect of 



I. the alteration in Kh,o ; 

 II. the alteration in Kgait- 



In brief, the increased acidity or alkalinity produced by increase 

 of temperature is greater (theoretically) than could have been 

 produced from increased dissociation of the salt. The significance 

 of this will be seen later. 



At present the point under consideration is the mechanism for 

 converting the potential energy of the food-stuffs into the kinetic 

 energy exhibited by protoplasm. Enough has been said to 

 indicate 



(1) That slight alterations in hydrogen ion concentration may 

 produce large alterations in surface tension (Chap. VI.). 



(2) That slight alterations in hydrogen ion concentration may 

 produce large alterations in the degree of dissociation of salts. 



(3) That the degree of dissociation of salts, acids and bases 

 governs the value of surface tension and osmotic pressure. The 

 next chapter deals with the inactivation of these factors. 



Further Keading 



Crocker & Matthews. "Theoretical and Experimental Physical 



Chemistry." J. & A. Churchill." 



