How many of the following are paramagnetic in nature?

i) Singlet carbine  ii) Triplet carbene      iii) Carbon free radical   iv) Carbocation v) Carbanion

(ii) & (iii) are paramagnetic.
A free radical maybe defined as an atom or group of atoms which contains an unpaired electron and it is paramagnetic in nature. They are formed by homolysis. If the unpaired electron is on carbon atom, they are called alkyl free radicals. Free radicals are highly reactive due to their unpaired electrons.