feli03
Badges: 3
Rep:
?
#1
Report Thread starter 3 years ago
#1
what and how sn1 and sn2 work? i can't understand it at all
0
reply
ngwengsamowo
Badges: 2
Rep:
?
#2
Report 3 years ago
#2
Same, I am here for an answer.
0
reply
herefortherepss
Badges: 1
Rep:
?
#3
Report 3 years ago
#3
what is sn1 and sn2??
0
reply
feli03
Badges: 3
Rep:
?
#4
Report Thread starter 3 years ago
#4
(Original post by herefortherepss)
what is sn1 and sn2??
a mechanism
0
reply
herefortherepss
Badges: 1
Rep:
?
#5
Report 3 years ago
#5
(Original post by feli03)
a mechanism
I am good with mechanisms but have never heard of sn1 and sn2 - is there a different name for them? I presume you're talkig about A Level chem?
0
reply
tchilly
Badges: 7
Rep:
?
#6
Report 3 years ago
#6
SN1 mechanism = a nucelophilic substitution that depends on 1 species in the rate determining step (unimolecular). It requires the formation of a carbocation intermediate that persists long enough to be attacked by the nucleophile since it is stabilised by the inductive effect of adjacent methyl groups, so it applies to tertiary and secondary (depending on the conditions) halogenoalkanes/alcohols. SN1 is fastest for a tertiary halogenoalkane and slowest for a primary halogenoalkane.

SN2 mechanism = a nucleophilic substitution that depends on 2 species (bimolecular) in the rate determining step and so it usually involves the collision of 2 species to form a transition state. It applies to primary alcohols/halogenoalkanes because the carbocation formed is not sufficiently stabilised by the adjacent methyl groups. The more sterically hindered a carbon atom, the less likely it is going to be attacked by a nucleophile so SN2 is fastest for primary halogenoalkanes and slowest for tertiary halogenoalkanes (since they are more "bulky").

If you are studying any of the new A level specifications you will encounter these terms in explaining the rate of hydrolysis of halogenoalkanes (core practical), deducing the rate determining step (slowest step) in a reaction using the rate law, using optical activity as evidence for a mechanism of a reaction (does the product result in an inversion of plane polarized light or a racemic mixture?)
2
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

What factors affect your mental health the most right now?

Anxiousness about lockdown easing (194)
5.05%
Uncertainty around my education (559)
14.55%
Uncertainty around my future career prospects (430)
11.19%
Lack of purpose or motivation (529)
13.77%
Lack of support system (eg. teachers, counsellors, delays in care) (190)
4.95%
Impact of lockdown on physical health (232)
6.04%
Loneliness (323)
8.41%
Financial worries (141)
3.67%
Concern about myself or my loves ones getting/having been ill (151)
3.93%
Exposure to negative news/social media (172)
4.48%
Lack of real life entertainment (218)
5.67%
Lack of confidence in making big life decisions (343)
8.93%
Worry about missed opportunities during the pandemic (360)
9.37%

Watched Threads

View All