The stability order of the following carbocations is:

Which of the following species $(A)$,$(B)$,$(C)$,and $(D)$ contain an $sp^2$ hybridized carbon atom? $(A) CH_3^+$,$(B) CH_3^-$,$(C) dot{C}H_3$,$(D) :CH_2$

The order of stability of carbonium ions is:

Arrange the following anions in decreasing order of their stability:
$CH_3^{\Theta}, NH_2^{\Theta}, OH^{\Theta}, Cl^{\Theta}$

Which of the following compounds forms the most stable carbocation: $(CH_3)_3C-Br$,$(C_6H_5)_3CBr$,$(C_6H_5)_2CHBr$,and $C_6H_5CH_2Br$?

Arrange the following free radicals in order of decreasing stability:
$(A)$ Cyclohexyl-CH2-CH2•
$(B)$ Cyclohexyl-$CH$•-CH3
$(C)$ Cyclohexyl=$CH$-CH2•
(Note: The dot represents the radical center.)