STEREOCHEMISTRY

Ans..Only 1 and 4 are optically active..
2 there is plane of symmetry
3 plane of symmetry..
5 wen u rotate the grp on the 2nd carbon in anticlockwise direction..u will get a meso compound though it has two chiral carbons.but it is optically inactive due to internal compensation

@GOVIND....1 IS OPTICALLY INACTIVE...DUE...TO PLNE OF SYMMETRY..PLANE IS ALONG..DA METHYL GRPS

Nahi hai yaar plane of symmetry 1 mein...Optically Active it'll be.

PLANE OF SYMMETRY NAHIN HAI YAAR SO 1 WILL BE OPTICALLY ACTIVE BUT HAS NO CHIRAL CARBON CENTRE...

1 and 4 agreed with govind

1,4,5 are chiral but 2 and3 are not.
first of all attached to a carbon must be different.

for instance:here at tert. carbon all the 4 groups attached to it are not different so not chiral.

YAAR KATOCH 1 KAISE CHIRAL.........
1 MEIN TO CHIRAL CARBON NAHIN HAI........
AGAR HAI TO BATA KAHAN........

5. is meso
3. plane of symmetry
1. active .. using RS.. i get both chiral carbons as R,R

not sure abt the rest

ans==
1.chiral
2.chiral
3.not chiral
4.chiral
5.not chiral