Monochlorination of propane yields two constitutional isomers, and dichlorination yields four

Monochlorination of propane yields two constitutional isomers, and dichlorination yields four. Trichlorination yields five constitutional isomers. Draw all five trichloropropane isomers. CH3CH2CH2Cl CH3CHClCH2Cl CH3CCl2CH3 CH2ClCH2CH2Cl CHCl2CH2CH3

The Correct Answer and Explanation is:

The monochlorination, dichlorination, and trichlorination of propane (C3H8) produce several constitutional isomers based on where the chlorine atoms are substituted. Let’s break down the trichlorination process and draw all five constitutional isomers:

Trichlorination of Propane (C3H8):

1. Isomer 1: CH3CH2CH2Cl
   • Chlorine attached to the first carbon of the propane chain (primary position).
   • This is one of the simplest monochlorinated products.
2. Isomer 2: CH3CHClCH2Cl
   • One chlorine on the second carbon (secondary position) and one on the third carbon (primary position).
   • A dichlorinated isomer created by adding chlorine to both the middle and the end of the chain.
3. Isomer 3: CH3CCl2CH3
   • Chlorine attached to both carbons of the middle carbon (secondary positions).
   • This creates a dichlorinated isomer with two chlorines in the middle carbon.
4. Isomer 4: CH2ClCH2CH2Cl
   • Chlorines are placed on both the end carbons, making this a symmetrical trichlorinated propane.
5. Isomer 5: CHCl2CH2CH3
   • Chlorine on the first carbon and two chlorines on the second carbon (secondary position).
   • This gives another distinct trichlorinated configuration.

Each of these compounds follows the idea that the placement of chlorine on different carbons of the propane chain leads to different isomers, where the carbon chain structure changes while maintaining the molecular formula.

Explanation:

In trichlorination, three chlorine atoms are introduced to propane. These can be attached in various positions along the carbon chain. The positions can be primary (attached to a terminal carbon), secondary (attached to a middle carbon), or tertiary (attached to a carbon bonded to two other carbons). Since the chlorine atoms can be arranged in different configurations, the result is a set of isomers that have the same molecular formula but different structural arrangements.

The number of possible isomers increases with the number of chlorine atoms, leading to 5 distinct trichlorinated isomers for propane.

I’ll now draw the structures for the five isomers.