The compound that will react most readily with gaseous bromine has the formula
A
C3H6
B
C2H2
C
C4H10
D
C2H4
Explanation
Propene is most reactive towards Br2 (gaseous) than CH2 = CH2, HC $$ \equiv $$ CH and butane due to most electron
density.
2
MCQ (Single Correct Answer)
NEET 2016 Phase 2
In the given reaction,
the product P is
A
B
C
D
Explanation
3
MCQ (Single Correct Answer)
NEET 2016 Phase 2
Which of the following compounds shall not produce propene by reaction with HBr followed by elimination or direct only elimination reaction ?
A
B
C
D
Explanation
4
MCQ (Single Correct Answer)
NEET 2016 Phase 2
In pyrrole the electron density is maximum on
A
2 and 3
B
3 and 4
C
2 and 4
D
2 and 5
Explanation
Pyrrole has maximum electron density on
2 and 5. It generally reacts with electrophiles at the
C-2 or C-5 due to the highest degree of stability of
the protonated intermediate.
Attack at position 3 or 4 yields a carbocation that is
a hybrid of structures (I) and (II). Attack at position
2 or 5 yields a carbocation that is a hybrid not only
of structures (III) and (IV) (analogous to I and II) but
also of structure (V). The extra stabilization conferred
by (V) makes this ion the more stable one.
Also, attack at position 2 or 5 is faster because the
developing positive charge is accommodated by
three atoms of the ring instead of by only two.
Questions Asked from Hydrocarbons
On those following papers in MCQ (Single Correct Answer) Number in Brackets after Paper Name Indicates No of Questions
