Question

How many structural isomers with the formula `C_4H_10O` are possible?

Answer 1

There are seven isomers.

Explanation:

The formula for butane is `"C"_4"H"_10`.

Thus, the formula `"C"_4"H"_10"O"` tells us that the compound is saturated, so it can be either an alcohol or an ether.

Isomeric alcohols

First, draw all the isomers of butane.

You get

`color(white)(mm)"butane"color(white)(mmm)"and"color(white)(mm)"isobutane"`

Second, put an `"OH"` group on every carbon atom that does not give you a duplicate structure.

You get

`color(white)(mm)"butan-1-ol" color(white)(mmm)"butan-2-ol" color(white)(m)"2-methylpropan-1-ol"color(white)(m)"2-methylpropan-2-ol"`

Ethers

Draw the isomers of butane as before and put an `"O"` atom between every possible carbon that does not give a duplicate structure.

You get

`"methyl propyl ether"color(white)(mmmmmmm)"diethyl ether"color(white)(mm)"isopropyl methyl ether"`