Question

Total number of possible Alkyl chlorides with the formula ${C_4}{H_9}Cl$ is/are.

Answer 1

Hint : This question asks us about the possible alkyl chlorides of formula ${C_4}{H_9}Cl$ . This is possible when the formula remains the same, but only the position of substituents changes. Hence, we can say that indirectly the question is asking us about the isomers of the given compound. Consider the places where chlorine can be displaced and different configurations of the main chain should be considered while answering it.

Complete Step By Step Answer:
Let us understand, firstly about the isomers.
Isomers are species which have the same molecular formula but different structure.
Let us take an example of butane and isobutene, both of these are having the same molecular formula that is ${C_4}{H_{10}}$ , but when it comes to the structure, butane is a straight chain and isobutene is having a branch of methyl group at 2nd carbon.
Coming, back to the question, we are given the molecular formula ${C_4}{H_9}Cl$ and we have to mention the total number of possible alkyl chlorides or isomers of alkyl chloride.
First, we can place the Cl atom in two different positions, giving two different structures which are $1$ -chloro-butane and $2$ - chloro-butane. The structures are shown below:

After this, we can change the position of methyl groups and get two more structures which are $2$ -chloro- $2$ -methylpropane and $1$ -chloro- $2$ -methylpropane. The structures of both are as follows:

Therefore, we get four possible alkyl groups with the formula ${C_4}{H_9}Cl$

Note :
We have to keep in mind the fact that isomers are having similar molecular formulas and due to that they have the same weight, but isomers are having different molecular structure configuration and due to this they have different physical properties but similar chemical properties. There is no shortcut for this, we need to practice drawing different types of isomers.