i) State one use each of DDT and iodoform.
ii) Which compound in the following couples will react faster in S2 displacement, and why?
a) 1-bromopentane or 2-bromopentane
b) 1-bromo-2-methylbutane or 2-bromo-2-methylbutane
ii) Which compound in the following couples will react faster in S2 displacement, and why?
a) 1-bromopentane or 2-bromopentane
b) 1-bromo-2-methylbutane or 2-bromo-2-methylbutane
Solution
(i) DDT is used as a powerful \textbf{insecticide} (against mosquitoes/lice); iodoform is used as an \textbf{antiseptic} for wounds (action due to liberated iodine).
(ii) S2 needs an unhindered backside approach (1° > 2° > 3°):
(a) \textbf{1-Bromopentane} (primary) reacts faster than 2-bromopentane (secondary).
(b) \textbf{1-Bromo-2-methylbutane} (primary) reacts faster than 2-bromo-2-methylbutane (tertiary).
(ii) S2 needs an unhindered backside approach (1° > 2° > 3°):
(a) \textbf{1-Bromopentane} (primary) reacts faster than 2-bromopentane (secondary).
(b) \textbf{1-Bromo-2-methylbutane} (primary) reacts faster than 2-bromo-2-methylbutane (tertiary).
CBSE Class 12 Board · 2010 · Delhi · Subjective