i just remembered one more
in the reaction,
C2H5.                     C2H5 
    I                           I  
H-C-CH3 giving CH3-C-H
    I                          I
CHO                       COOH.
a)configuration is reversed b)configuration is retained.
c)new steiocentre is created d)steriochemistry cannot
be discussed for the rxn.

if i remember more i will post here tomorrow.