battery questions (1 Viewer)

[Pace_T]

hey all
i continually come across questions in exams that specifically ask about one of the batteries
from the syllabus i chose fuel cell and dry cell
did the syllabus change from knowing all of them(or most) to allowing u to choose which ones u wanted to do?

also, with dry cell, the MnO2 is reduced to Mn2O3 or Mn(OH)3? I think the difference here is that one of them is an alkaline cell while the other is just a dry cell (dry cell being the former result) but im not too sure.
thanks.

 

[Captain Gh3y]

I'm pretty sure the syllabus says 'one of' and so you'd have a choice if it were in the HSC.

In a dry cell, the cathodic reaction is
2MnO_2(s) + 2H⁺_(aq) + 2e^- --> Mn₂O₃ + H₂O_(l)

The alkaline cell uses the OH instead.