GS-2 Physical Sciences Question 24

[li5504552]

I am confused why c would not be right? If electrolytes are added, there would be more dissociation, and wouldn't there be more ions and thus greater solution pressure? Thanks.

[admin]

Le Chetalier's rule would suggest that if you wanted to increase the rate of rusting, you would want to remove the products (ie, reduce electrolytes = reduce solution pressure).

[kbshah6109]

I understand what an electrolyte is - a charge carrier in solution.
But I don't understand why C a possible answer choice.

If you increase the solution pressure of Iron, that would be you are increasing the mole fraction of iron. Thus, by Le Chat principle, then you will increase the iron ions in solution, which can then react with hydroxide to rust.

Am I miss understanding something?

[admin]

Your logic is very good except for one problem: what mechanism would you propose to explain "why" the solution pressure for the iron is increased. The answer is answer choice B.

Answer choice C is true but it does not answer the question. This is a type of question that you will see from time to time on the real exam.

[oscarcstll2813]

I agree, but the question is asking why, not how.