1.

When acidulated water (dil. H_(2)SO_(4) solution) is electrolysed,w ill the pH of the solution be affected ? Justify your answer.

Answer»

Solution :* There is no change in PH value. pH value depend on the `H^(+)` ION concentration of any solution.
* In acidic water, electrolysis of dilute solution of `H_(2)SO_(4)` gives following reaction.
`H_(2)SO_(4) to 2H^(+)+SO_(4)^(2-)`
* Reduction of `H^(+)` ions is carried out near cathode.
`2H^(+)+2e^(-) to H_(2(g))`
* On the surface of anode `H_(2)O` get oxidized not `SO_(4)^(2-)` ion
`H_(2)O_((l)) to (1)/(2) O_(2)+2H^(+)+2e^(-)`. . . (ii)
OVERALL reaction=(i)+(ii)
`H_(2)O_((l)) to H_(2(g)) +(1)/(2)O_(2(g))`
* So, in this reaction, concentration of `H^(+)` or `OH^(-)` ions does not change. So, pH remains CONSTANT.


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