1.

How will the pH of brine (aq. NaCl solution) be affected when it is electrolysed ?

Answer»

Solution :* The PH of the solution will RISE an NAOH is formed in the electrolytic cell.
* In electrolysis of cathode of brine (NaCl) solution, reduction of `Na^(+)` does not occur on cathode but the reduction of `Na^(+)` does not occur on cathode but the reduction reaction of water on cathode gives `(H_(2)+OH^(-))`.
`2H_(2)O_((l))+2e^(-) to H_(2(g))+2OH_((aq))^(-)`.. . . . (Reduction)
and `pOH= -log_(10)[OH^(-)]`
* So, `[OH^(-)]` INCREASES, pOH also increases and pH decreases.
For understanding : `[OH^(-)]=0.1M`
then pOH=0.01M then pOH=2 and pH=12
So, `[OH^(-)]` increases, pOH also increases and pH get decreases.


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