MULTI ANSWER
Q1. Which of the following statements are wrong
(a) A meso compd has chiral centres but exhibits no optical activity
(b) A meso compd has no chiral centres thus are optically inactive
(c) a meso compd has molecules which are superimposable on their mirror images even though they contain chiral centres
(d) a meso compd is optically inactive because the rotation caused by any molecule is cancelled by an equal and opposite rotation caused by another molecule that is the mirror image of the first
29I think the answer shud be B,C,D
D is incorrect bcoz it is the case of racemic mixture which do not exhibit optical activity due to external compensation and in meso optical activity is not there due to internal compensation..
edited...sry didnt read the question properly Which of the following statements are wrong
13d) is rite 'coz, meso mein optical activity "internally" cancel hoti hai.... If one-C is "Rectus", doosra "SInister" hoga, equal n opposite rotation.
13Racemic aur Meso mein bas thoda sa fark hai, the action/result is the same.
Fr racemic, we shud have 2 "different" compounds (but enantiomers of each other), one-dextro, another leavo, so they cancel out each other's rotation externally.
In meso, there are two equal & oppositely rotating chiral centres in the "same" one compound. But still, effective rotation will be zero, Isliye internally cancelled.
13BY "another molecule" they don't mean another compound,,,,matlab another chiral molecule in the same compound.
29in option d there are two molecules which are cancelling each other's optical rotation which happens in racemic mixture and not in meso...so D shud be incorrect..
