Was the last one 2 only?
@sattake Neither of them contained aldehydes, so the answer was (D).
The organic questions were:
- acid catalyst
- CH3I reacts fastest
- 5 resonance structures
- neither I nor II
- nitrobenzene (aromatic ring with NO2 attached)
- urea denatures it
I got two of those wrong…
Did anyone know which apparatus was right to separate the mixture? Question #12 or something.
@1golfer1 I put b, but realistically I had no idea for number 12. Do you happen to remember if the answer to the urea one was a. for the first page. was the graph increasing then flat, and was the precipitate Ag2So4 only. Also, I’m pretty sure lactose is an aldose. Do you have a source that says otherwise? Also what was the correct answer for the Nitrogen phase question?
@sattake Yep, it looks like you’re right… I am waiting for college to develop my higher-level orgo knowledge, but appears that lactose undergoes hydrolysis and does some weird “open-chain” stuff to form an aldehyde. If that is actually correct, very few (maybe a tenth) of people are going to have gotten that one.
Nitrogen – I remember the answer having something to do with sublimation because the pressure was below the triple point.
Ag2SO4 – That is what I picked, but the question was vague as to whether the H2SO4 was added to the filtered precipitate or to the filtered solution. Former = Ag2SO4; Latter = BaSO4.
Urea – Yes, “increasing and then flat” because the other reactant was limiting.
Question 12 – I actually think (B) is right, lol. That corkscrew thing is apparently used in distillation procedures. I took a complete guess on that one.
Was the safest way to do a flame test the “dissolve in methanol” option? That question was so random. I laughed like crazy though when I read the first choice:
“Meh, let’s just stand a few feet away and throw some of it onto an open flame.”
Also, for the laboratory practical, did anyone get that the acid was triprotic? Because I didn’t, nor did anyone else I know…
please delete your comments, guys. its very possible that there were extensions, so best be safe and delete them
the lab’s acid was triprotic and the order of the reactions were 1 and 1 according to the answer key that the local sections revieved
also shouldn’t the tertiary alkyl halide react fastest because of the steric hindrance that it has? i think in 2012 part 2 thats what it says. specifically, the tertiary iodide would react fastest because thats the best leaving group.
@bmebois I actually put the tertiary one myself but mostly everyone told me I was wrong. I never bothered to look it up, but here is what I found – (CH3)3CI ins’t just faster than CH3I, it is over one million times faster.
Everyone thinks the lab is easy, and then gets reaction orders of 1 and 0 and dirprotic.
Did you guys get 4.65 for the ph of the Hcn complex. Also did you get both 1 and 2 for that lab question with naoh
Oh and the flame test had something to do with a wooden splint lol
Question 12 was definitely the Büchner funnel, to filter out the precipitate.
What was the Ag2(SO4) question again? I can’t exactly remember.
The flame test was to dissolve in methanol and ignite in crystallizing dish.
Also, the tertiary iodide would react the fastest.
@sattake The methanol flame test method I picked was actually used by a teacher in a classroom demonstration a few years ago… He killed one of his students…
NaOH titration was just one of them. Choice I gave too many grams and Choice II gave to many moles, if I remember correctly.
How did you get 4.65 for the pH…?
@ParadoxChem126
Do you have a source for that flame test one?
There was not a percipitate on #12 – I think it was a volatile mixture or something.
The Ag2SO4 one was like, first you add NaCl to a solution possibly containing four ionsx and then you had H2SO4 to the filtrate.
We can’t even get the right answer with multiple people here.
12 were crystals of something, I remember.
The flame test I know from experience. Plus, wooden splints introduce a yellow color to the flame which interferes with your results.
The titration was neither, if I remember correctly.
If you add sulfuric to the filtrate, then only BaSO4 precipitates.
Is it confirmed that the orders were 1 and 1? I’ve been told they were 1 and 2 D:<
For the lab practical? I’ve heard that they are 1 and 2 but I am not entirely sure either.
our local section gives us the answers right after we did the lab, and although ive been hearing 1 and 2 (and websites have been showing this), the section says 1 and 1
I found the studies online, and it is indeed second order with respect to iodine… did anyone get that?
yup
mainly i dont get how the acid could’ve been triprotic…