Q.1-1-25a - Organic Chemistry (Mcmurry)

Question

Why can’t molecules with the following formulas exist

a) $C{H}_5$ (b) $C_2{H}_{6}N$ (c) $C_2{H}_{5}Br$

Step-by-Step Solution

Answer

Answer

The formula  can’t exist because carbon valency is four. It can form four single bonds with hydrogen. Thus, it can’t create the given molecule.

Step 1: Fundamentals about bonds

The number of bonds that some atoms form is represented as follows.

A structure requiring these atoms to exceed these numbers of bonds is impossible because it requires that the traces exceed the number of electrons that fit into its outer shell.

Step 2: Given molecule can’t exist

The formula requires that carbon exceeds four bonds or hydrogen exceeds one bond.

Step 3: Structure of C H 5

The structure cannot exist due to the inability to form of bonds by the carbon.

Evidence for non-existence is given below.

                                             C-H bond formation