Question

Hi,
I am stuck on this question and would appreciate some guidance. The question states " The value of Kw decreases as the temperature decreases. Is the auto-ionization of water an exothermic or endothermic reaction in the forward direction?"
I feel like the answer should be exothermic as I know from studying Le Chatelier's principle that a decrease in temperature favours the reaction to occur in the forward direction. Is that a correct assumption?

Answers

bobpursley
ionization decreases as temp decreases so..
ionization increases as temp increases
water+heat>>ions

endothermic
bobpursley
ionization decreases as temp decreases so..
ionization increases as temp increases
water+heat>>ions

endothermic, so decrease in temp favors reverse.

check my logic
bonjo
when temp decreases, water will decrease in solubility or in ionization and the reaction will favour the backward reaction;

H+ + OH- --> H2O

so we know that the backward reaction is endothermic and the forward is exothermic.

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