Reduction potential

[匿名]

2011-04-10 1:14 am

OXYGEN的REDUCTION POTNETIAL就有2條,一條係(I) O2+2H2O->4OH- 另一條係(II) O2+4H+->2H2O ,
如果一條題目涉及OXIDATION OF METAL BY AIR. 甘係用(I) OR (II)?

仲有一條REDOX REACTION,果E VALUE要至少幾多先係FEASIBLE?
好似06 P1 Q1C, 點解V3+ 唔會OXIDIZE 到V5+? 而係4+就停 THX A LOT~

回答 (1)

己式庚辛

2011-04-12 2:41 am

✔ 最佳答案

1.
use equation (I).
you don't have the acid but water. so why using equation which requires acid?
also, notice that rusting involves conversion of iron to iron hydroxides as intermediate steps. after that, dehydration gives iron oxides.

if needed, you can estimate the reduction potential for cases with specific concentrations, using Nernst equation.

2.
i don't have past papers on hand. please post the question up for our reference.

the overall cell voltage has to be positive.

👍 0 👎 0