Chemistry MCQ thread...

[Serenity]

SOMEONE please explain me the answer of November 2006 question 9

 

[RafaySid]

Woah man!! Check out this!!
http://www.benjamin-mills.com/chemistry/structures/

 

[Octahedral]

 

[kshumaila52]

ans is d (only 1 is correct) as tertiary halogenolakne shows 2 step reaction(SN1)

 

[RafaySid]

@Octahedral
Dude, it seems you're really into Nov 2010's paper, and I did that too today . It's D because as far as I think only in 1 will there be Sn1 reaction as that compound is a tertiary alkyl halide.

 

[Zishi]

thats an R rated questiom

It was really tough question - I got the answer after taking a lot of time. Is the answer 2^7?

 

[shyqueen]

plz sumbody post da markscheme of M/J 2000 n 2001... plzzzz!!

 

[kshumaila52]

plz sumbody post da markscheme of M/J 2000 n 2001... plzzzz!!

I it is not available....i used my all resources but

 

[RafaySid]

thats an R rated questiom

It was really tough question - I got the answer after taking a lot of time. Is the answer 2^7?

Would you mind sharing? But I think such questions isn't our part of the syllabus now which require mathematical formulae of isomers or what.. What do you ppl say?

 

[Zishi]

thats an R rated questiom

It was really tough question - I got the answer after taking a lot of time. Is the answer 2^7?

Would you mind sharing? But I think such questions isn't our part of the syllabus now which require mathematical formulae of isomers or what.. What do you ppl say?

Well, I don't want to mess up the minds of other people at XPF by posting incorrect explanation(just in case if my answer is wrong). And yeah, there's a very low chance of this question coming in a real paper.

 

[hassam]

well its 2^7...zishi...but i dint understnd a single bit abt this question ........cn u explain

 

[hassam]

well need help on this question

 

[hassam]

well need help on this question......how i ll figure out valency of Cl in CrO2Cl2....???

 

[Zishi]

well its 2^7...zishi...but i dint understnd a single bit abt this question ........cn u explain

YAY! I got the correct answer for this much tough question... :Yahoo!:

Explanation, I guess is quite difficult, cuz I used like 3 pages of my notebook to get my answer. But here you go:

What can I say is that as there are 6 chiral centres, so there must be 2^6 isomers (times) 2 for cis-trans isomers with H atom(on carbon atoms bonded to a carbon atom with a hydroxyl group) on it.

So 2 x 2^6 = 2^7

 

[Zishi]

well need help on this question......how i ll figure out valency of Cl in CrO2Cl2....???

Cr + 2(-2) + 2(-1) = 0

Cr = +6
D, is the answer.

 

[hassam]

SO2Cl2...how to work valency of sulfur in this compound

 

[hassam]

then where's that rule that said most electronegative element was given the -ve oxidation no.

 

[Zishi]

then where's that rule that said most electronegative element was given the -ve oxidation no.

There are two more electronegative species in it now. So there will be two negative charges and and +ve charge.

 

[Zishi]

SO2Cl2...how to work valency of sulfur in this compound

Sulfur's oxidation is +6 in it - used same way as that of chromium's. I confirmed my answer by drawing covalent bonds, sulfur has formed 6 covalent bonds in this compound.

 

[histephenson007]

Ok guys... thats it for me today¬
I'm going to sleep
A VERY BIG THANK YOU FOR EVERYONE!!! I've learned a lot from this thread!
Good luck and Godspeed for everyone taking the test tomorrow¬
Have fun doing it!!!