Destroyer Chem questions

[DenTony11235]

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Answer to question 135 states that ClO4(-) is a weaker base than HClO4. I get that HClO4 is considered an acid not a base, but can anyone agree that that is very tricky and unfair? Is a strong acid not in any respect considered a base?

Question 144 asks which elementary step would be least likely to occur and one of the choices is: 2X -> X + Y .... And it's not even the answer. Wtf is 2X -> X + Y I can't think of a single example of that, hence making it the least likely to me. Unless an impossible event is not considered "least likely" because it just won't happen. But this is science, dammit, never say never.

 

[steppingstone]

I think the first question makes sense because ClO4- is the conjugate base of a strong acid which makes it a weak base therefore it is a weaker base.

I also looked over the second question again for a quick second when I was doing destroyer because I remember it being weirdly worded, especially without actual compounds on there so I agree it's a bit twisted!!

 

[DenTony11235]

Well an acid is more acidic than its conjugate base. Making it more weakly basic. Whatever I'm banking on something like that not even showing up.

 

[IsaacYankem]

2X --> X + Y

2 H202 --> 2H2 + 2O2

The first question you mentioned boned me a few times. I read it that since Perchloric acid is a strong acid, it's clearly not a base. But their explanation clarifies that ClO4- is the correct choice as it's the conjugate of a strong acid. But yeah, fell in to that trap more than once.

 

[FeralisExtremum]

This question is just about being able to identify that HClO4 is not a base in any respect. There are molecules out there that are amphoteric (e.g. H2O), but the strong acids are not among them. I understand where you are going with your logic of an acid being "less basic" than its conjugate base, but if something doesn't react as a base at all, you can't categorize it as such - even as a super weak one.

 

[DenTony11235]

2X --> X + Y

2 H202 --> 2H2 + 2O2

Well, that doesn't exactly fit the profile. I think its incorrect because its simply impossible.

As far as HClO4 goes, I mean, I'll let it go and not wonder about it any longer, though that sucks.

 

[IsaacYankem]

Well, that doesn't exactly fit the profile. I think its incorrect because its simply impossible.

This should explain it better: http://en.wikipedia.org/wiki/Chemical_decomposition

Ferralis is on point with the explanation of HClO4