[Abeer88]

Hello 
What are the bulky groups mean ?
How I can know if the compound have a bulky group or not ? / by another way --> how I can arrange some of compounds depending on presence of bulky groups
Please help me , My exam tmw
My q may be in wrong way ,  but plz tell me every thing about bulky groups

[Borek]

Bulky means large. It occupies a lot of space and can't easily fit. 5 second googling to locate this information.

[Abeer88]

How Can I differentiate between primary halides depending on bulky groups in them?

[Abeer88]

The question is -->
rank these compounds in order of decreasing reactivity toward SN2 reaction?
_____________
Ch3Ch2Ch2Ch2Br > (Ch3)2Ch2Br 
how is that ?

[OsmiumTetroxide]

Its very simple...
bulky groups are those which occupy large spaces causing hindrance to attacking species
eg:- ethyl groups...

what happens if bulky groups are present?
ans:- it changes the type of reaction
i.e, t-butyl alcohol undergoes elimination or sn1 while me-OH undergoes primarily SN2

in ch3ch2ch2Br nucleophile can easily attack Carbon attached to Br since there is no hindrance (only small H atoms are nearby)..
but in the 2nd compound, C attached to br is hindered by two ch3 atoms.(repulsions occur between 2 ch3 and 1 Nucleophile which is not favourable for SN2).