Please help !! Answer the following questions. Use examples in order to explain your answers

1. What is the effect of molecular weight (M. wt.) on melting and boiling points of alkanes?

2. What is the effect of branching on melting and boiling points of alkanes?

3. What ara the differences between the homolytic and heterolytic bond dissociation ? And why homolytic dissociation energy of H-H (104 KJ/mol) is lower than its heterolytic bond dissociation energy (401 KJ/mol)?

1) boiling points increase as molecular weight increase and vice versa. This is due to the increase in van der waals forces between molecules.
2) branching decreases the melting and boiling i.e increase in branching decrease boiling point and melting point. This is due to the fact that there are less point of contact between neighbouring molecules, so molecules are farther apart from each other, which means weaker van der waals(London forces) less energy is required to overcome these force of attraction.
3) In homolytic fission each of the fragment retain one of the bonded electron and radicals are made if the molecule is neutral. In heterolytic fission one fragment gets both bonding electron.
The energy for the heterolytic fission is higher because energy is not only needed to break the covalent bond but also to overcome the force of attraction between oppositely charged ions formed.

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