`a.` Convert butan`-1-`ol to `3-`chlorobutan `-2-`ol.
`b.` Convert propene to`:`
`i.`. `1-`chloropropane, `ii.` `2-`chloroproopane, `iii.` `2-`methyl pentane, `iv.` `2,3-`dimethyl butane , and `v.` pentane.

Explanation

`a.`
Here, the `(-OH)` group is changing from `C-1` to `C-2` and `CI` is added to `C-2`, with the same number of `C` atom.

`b.` `i.`
If we add `HCI` it will add according to Markovnikov's rule and will give `2-`chloropropane.
First, bring one `(-CI)` group at allylic position and then carry out hydroboration followed by protonolysis with `CH_(2)COOH`.

`ii.`
`iii.`
First, convert propene to `1-`chloropropane as in `(i)`, and then carry out Corey `-` House synthesis.

`iv.`
First, convert propene to `2-` chloropropane as in `(ii)` and then carry out Cory `-` House synthesis.
`v.`
First, convert propene to `1-` chloropropane as in `(i)` and then carry out Corey `-` House synthesis.