Calculate pH of a 1.0 xx 10^(-8) M solution of HCl.

1.	Calculate pH of a 1.0 xx 10^(-8) M solution of HCl.
Answer» Solution :The complete ionization occurs of strong acid HCI. Thus, [HCl]=`[H^+]=1.0xx10^(-8)`M Because of self ionization of water, the `[H_3O^+]` also present in solution, So, Hydrogen ion concentration of HCl is less than `[H_3O^+]` of water therefore `[H_3O^+]`of water is taken in calculation. Self ionization of water : `2H_2O_((l)) HARR H_3O_((AQ))^(+) + OH_((aq))^(-)` `K_w=[H_3O^+][OH^-]=1.0xx10^(-14)` ....(Equation ) Suppose from water `[H_3O^+]=[OH^-]=1xx10^(-7)`M TOTAL `[H_3O^+]` in solution =(`[H_3O^+]` of water ) + (`[H_3O^+]` of HCl) `=(1xx10^(-7)+1xx10^(-8))` M `=1.1xx10^(-7)` M `pH=-log [H^+]=-log (1.1xx10^(-7))` =-(0.0414-7.0)=(-6.9586)=+6.96

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