The number of shared pairs of electrons in propane is

In the alkane $CH_3-CH_2-C(CH_3)_2-CH_2-CH(CH_3)_2$,identify $1^{\circ}$,$2^{\circ}$,and $3^{\circ}$ carbon atoms and give the number of $H$ atoms bonded to each one of these.

Which reactions are difficult for alkanes?

Complete the reactions:
$CH_3(CH_2)_4CH_3 \xrightarrow[anhydrous \ AlCl_3, HCl_{(g)}]{isomerization} ?$
$n-\text{hexane} \xrightarrow{aromatization} ?$

Which of the following reactions proceeds via a secondary free radical?

Which of the following has the minimum boiling point?