paper 12 chemistry ...

[creative22]

Can someone tell me the question number of the question to which answer was 3 possible products was B ?

 

[creative22]

Also the answer and question number of XYZ one

 

[msohiabch]

Can someone tell me the question number of the question to which answer was 3 possible products was B ?

that was 23 i guess if you are talking about addition of HBr to the two given bromo alkenes...

 

[msohiabch]

Also the answer and question number of XYZ one

that was 28 i guess in which octene was given for cracking and there were 4 products WXYZ..
what ans did you give??

 

[Saad Sarfraz]

I did B as well=/

D use it by applying Kc. in the end i got x/2 moles. meaning 2 moles of P for 1 mol of Q

 

[Saad Sarfraz]

CO is ryt... ....chkd on google

did all 10 years past papers this question had appeared 5 times before ANS was nitrogen

 

[Saad Sarfraz]

wat was the answer for crckng thngy?

Im sure that the options which contained the product alkane was incorrect..alkenes dont produce alkanes when cracked. i went for D as W and X only because Z had too double bonds..

 

[Saad Sarfraz]

it wasnt bond energy it wz C bond length nd bond polarity a repeated Q

LMAO there is something known as a data booklet which is given during the exam. IF u had known its proper use u wouldve choosed A

 

[Ash1994]

What was the bond energy question again? I forgot my ans

 

[ash nadeem]

wat was da ans for HBr n optical isomerism ques?

 

[msohiabch]

wat was da ans for HBr n optical isomerism ques?

for HBr it was B

 

[msohiabch]

Im sure that the options which contained the product alkane was incorrect..alkenes dont produce alkanes when cracked. i went for D as W and X only because Z had too double bonds..

i also did D for this one but my all other fellows were saying that when cracking is done there is possibility of any product but smaller then the initial hydrocarbon. but i did by seeing number of carbons of products with octene.

 

[AppleGreen]

any one for Christ shake ,please do answer my question.

it is A, all of them

 

[likosp]

it wasnt bond energy it wz C bond length nd bond polarity a repeated Q

which year is it repeated from ??

 

[ash nadeem]

n d

for HBr it was B

N da optical one was it A!!!

 

[Beaconite]

The cracking of octene one was D. Because to balance no. of hydrogen atoms, the diene and alkane should both have been produced, or neither. This was the case only in A or D. And in A, the no. of carbon atoms weren't balanced, so answer is D.
The HBr one was either A or B, anyways it was the option with
(CH3)2CH-CBr3,
(CH3)2CBr-CHBr2
CH3CBr2-(CH3)CHBr
As for the coniine question, it was a cycloalkane with a propyl group attached so either A or B. And with B, there was an imbalance of covalent bonds, so answer was A.

 

[Ahmadbasharat]

Option C was Correct for sure Something like 10.8 Kpa

yes it

 

[Ahmadbasharat]

hey wb dat questn...whch gas is more released in emissin in car exhaust....i go with carbonmonoxide??? sumone telin me water vapours :/

no its nitrogen its repeated qs

 

[Rashmit Arora]

its C for (2+x/2)...2P n 1Q n 1R...r produced...i solved it

It was D. Im pretty sure.. 3 moles on each side. 2P--> 1Q + 2R (Given the condition that the nof moles of P are 2+x/2 , where in x stands for the number of moles of R)

 

[Saad Sarfraz]

i also did D for this one but my all other fellows were saying that when cracking is done there is possibility of any product but smaller then the initial hydrocarbon. but i did by seeing number of carbons of products with octene.

Okay for some reason they are right except that alkane is not produced (1000% sure asked my chem sir after the paper). But it the question it said produced TOGETHER OR ALTOGETHER or something like this. Then i counted the number of Cs and Hs and only D looked right further more how can a 2 double bonds be produced from 1..lol