urgent: (1 Viewer)

[Aerlinn]

Why doesn't electrolysis always undergo the reactions predicted? I know about electrolyste concentration, gas pressures, what electrodes are, current, voltage, but I don't know how they impact, except for concentration, I think.
With the voltage one, should the voltage be much, much higher than an standard potential difference (if that makes sense, but i've only ever heard it mentioned in relation to galvanic cells...) to cause another reaction to happen, and why that is?
Does the cathode of an electrolytic cell react?
Help=great :wave:

 

[xiao1985]

pressure: if one side of the reaction involve a gas, then higher pressure would disfavor that side (eg, recharge of car battery, where H2 are evolved... you won't want the pressure to be high, in addition to the safety reasons)

as regard to voltage, it depends.... if reactant involve a gaseous substance, then you can expect it to be alot higher, comparing to a all liquid reaction.

 

[Aerlinn]

Okay.
Another urgent query: Does universal indicator contain high pH initially? So if you had a reaction and wastesting for pH increase, it would be hard to see?

 

[xiao1985]

all indicators (including universal) is slightly acidic by nature.... however the nature is mild and should not interfere with the colour change too much...

this is also the reason you won't add too much indicator to your solution...