Which of the following is true of the electronically conducting polymers such as polyaniline, polypyrrole and polythiophene?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → They are much lighter than normal metals and can be used for making light-weight batteries.
Some organic polymers conduct electricity like metals. Since they are made wholly of elements like carbon and hydrogen (and sometimes nitrogen, oxygen or sulphur), they are much lighter than metals and are used for light-weight batteries. They also keep the flexibility of polymers, so electronic devices made from them can bend like a sheet of plastic.
Why the other options are incorrect
Option (1) They conduct electricity by the movement of ions, as electrolytic solutions do. — Incorrect. These polymers are electronically conducting, like metals and graphite. Conduction by the movement of ions is electrolytic (ionic) conductance.
Option (2) They have zero resistivity, as superconductors do. — Incorrect. Zero resistivity defines superconductors, which are metals and alloys at very low temperatures and some ceramic materials and mixed oxides, not these polymers.
Option (3) They are composed mainly of metals such as copper and silver, along with carbon and hydrogen. — Incorrect. They contain no metal; they are composed wholly of elements like carbon and hydrogen and occasionally nitrogen, oxygen or sulphur.
NCERT (2026-27 edition):
Electronically conducting polymers – “…Since then several organic conducting polymers have been made such as polyaniline, polypyrrole and polythiophene. These organic polymers which have properties like metals, being composed wholly of elements like carbon, hydrogen and occasionally nitrogen, oxygen or sulphur, are much lighter than normal metals and can be used for making light-weight batteries.”