7 Octane, C8H18, reacts with bromine in the presence of ultraviolet radiation.
(a) What is the role of ultraviolet radiation in the reaction?
(1)
A to break the Br-Br bond only
B to break a C-H bond only
C to break a C-C bond only
D to break both the Br-Br and a C-H bond
ANSWER
A - to break the Br-Br bond only
(b) One of the steps of the reaction is shown.
C8H17• + Br2 → C8H17Br + Br•
What is the name of this step and the type of bond breaking that takes place in the bromine molecule?
(1)
ANSWER
Name of Step is Propagation and Type of bond breaking is hemolytic. Hence, Option D is correct answer.
(c) What is the overall equation for the reaction of octane with bromine?
(1)
A C8H18 + Br2 → C8H16Br2 + H2
B C8H18 + Br2 → C8H17Br + HBr
C C8H18 + Br2 → 2C4H9Br
D C8H18 + 3Br2 → 2C4H7Br + 4HBr
ANSWER
B C8H18 + Br2 → C8H17Br + HBr
