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

Question

Why can’t molecules with the following formulas exist

a) $C{H}_5$ (b) $C_2{H}_{5}N$ (c) $C_3{H}_{5}B{r}_2$

Step-by-Step Solution

Answer

Answer

The formula $C_3{H}_{5}B{r}_2$ can’t exist.

Step 1: Carbon Valency

Carbon can form four single bonds. In this case, one-carbon includes five bonds in one representation, which is impossible as carbon valency can’t exceed five.

Step 2: Given molecule can’t exist

In other representation, carbon forms three bonds which are one bond less for its stability. The formula $C_3{H}_{5}B{r}_2$ requires that carbon exceeds four bonds or be short of two outer shell electrons.

The representation is as follows.

         $C_3{H}_{5}B{r}_2$Molecule can’t form

         $C_3{H}_{5}B{r}_2$ Molecule can’t form