9th Jan Shift 2, wrong answers by NTA:
Q.12 Answer should be 3 , they have given 4(Reason: More hyperconjugation structures)
Q.14 Answer should be 2, they have given 1(Reason: Work is done by gas to compress spring. Thus, \Delta U = -10-2=-12 )
Can you explain how to do that decrease in CFSE question in our shift? Just a general idea
I didn't attempt it Let me take a look.
Rearrangement will happen in A. Ans is correct
The RDS for SN1 is the step before rearrangement. Rate is always determined by RDS. @Sourav_Kumar
@Sourav_Kumar don't you think hammare paper mai ans kafi wrong diye hai? i found 2 for phy and 3 for chem didn't do for math
Maybe. But i believe we check stability of carbocation primarily. So acc to me ans is correct
@Yash_Srivastava2 i haven't even checked. Don't intend to now. Himmat nahi hai.
btw @Sourav_Kumar pichli baar kiyte aaye the?
No. A similar type of problem was discussed in our class. I had made the same mistake(I thought that after re-arrangement more stable carbocation will be formed), but the fact is that we check rate of sn1 by the carbocation which is formed first, not after rearrangement(Check mechanism of SN1).
Q12 is correct. Shifting of plus charge takes place. Q14 is from physics or chem?
Anyways let me check once. Since you’ve told. @Akshat_Joshi I may be wrong.
I have explained the reason above. RDS of SN1 is before rearrangement. If you remember the Reaction Coordinate vs Energy diagram for SN1, the highest activation energy is required for generation of the first carbocation.
There are few questions in Himanshu Pandey where rearrangement of carbocation is involved to find the stability order of Sn1
It is from chemistry. But how does it matter? The answer still remains the same.
H will change bro. In physics H released is positive. H gained is negative. In chemistry H gained is positive H released is negative.
@Akshat_Joshi pls check for chem for my ques
FIrstly, the question talks about internal energy. Secondly, \Delta U = q+W is in chemistry where W is the work done on the gas, while \Delta U = q-W is in physics where W is the work done by the gas. The two expressions are essentially the same.
10kj of work is done to increase the internal energy but 2 kj escapes as heat so effectively only 8kj is the increase in the internal energy