2004 HSC shipwrecks (1 Viewer)

[serge]

How did everyone answer the question on KBr solution being electrolysed

what would form... Hydrogen and oxygen gas?

 

[Pace_T]

this is the way i answered it;
at the anode, the highest one in the reduction potential list is oxidised
so thats Br- --> 1/2Br2(l) + e-
at the cathode the lowest one in the reduction potential list is reduced
which is H2O + 2e- --> 1/2H2(g) + OH-

now i dunno why in successone it says that the oxidised Br- goes to Br2(aq), the list suggests it should be liquid form coz it is higher in the list
can soemone clear that up 4 me plz
thx

 

[serge]

highest emf value, or higher as in vertically on the page?

 

[Pace_T]

highest emf value, or higher as in vertically on the page?

higher on the page

higher emf value means its going down the page right? (because it goes more positive)
thx

 

[rama_v]

Always write down the possible products then choose the most positive value (thats the one that will occur), at least in standard conditions (1 M solutions, standard temperature etc. )