Question

The total possible stereoisomers of 1 -chloro-3-methyl pentane is (A) 2 (B) 3 (C) 4 (D) 5

Short answer

The total possible stereoisomers of 1-chloro-3-methylpentane is 2 (A) as there is only one chiral center (C2) in the compound, and using the formula 2^n, where n is the number of chiral centers, we calculate 2^1 = 2.

Step-by-step solution

Identify the compound structure and chiral centers

: First, let's draw the structure of 1-chloro-3-methylpentane: Cl | H3C – C – CH2 – CH(CH3) – CH2 – CH3 Now, we need to identify the chiral centers (asymmetric carbons) in this compound. A chiral center is a carbon atom that is bonded to four different groups. In 1-chloro-3-methylpentane, there is only one chiral center (C2), bonded to a hydrogen, a chlorine, a methyl, and an ethyl group: Cl | H3C – C* – CH2 – CH(CH3) – CH2 – CH3

Calculate the number of stereoisomers

: Now that we have identified the chiral centers, we can use the formula 2^n to calculate the total number of possible stereoisomers, where n is the number of chiral centers. In our case, we have one chiral center (n = 1): Number of stereoisomers = 2^1 = 2 Hence, the total possible stereoisomers of 1-chloro-3-methylpentane is 2. So the correct answer is: (A) 2

Key concepts

Chiral Centers

In the realm of organic chemistry, chiral centers play a crucial role in the formation of stereoisomers. A chiral center, often referred to as an asymmetric carbon atom, is a carbon atom attached to four different groups. This arrangement makes the molecule non-superimposable on its mirror image, much like how your left hand is different from your right hand.
Chirality is significant because it directly influences the molecule's properties and reactions in biological systems. For example, the flavors and smells of some compounds change with different chiral forms. In 1-chloro-3-methylpentane, identifying the chiral center is key to determining the number of stereoisomers. In this molecule, carbon 2 is the chiral center as it is bound to four different substituents: a chlorine atom, a hydrogen atom, a methyl group, and an ethyl group.
Understanding how to pinpoint these centers is essential for anyone studying organic chemistry as it is the first step towards understanding a molecule's stereochemistry.

Organic Compounds

Organic compounds are the backbone of organic chemistry, characterized by the presence of carbon atoms bonded together, often along with hydrogen, oxygen, nitrogen, and other elements. The world as we know it, from the clothes we wear to the food we eat, is built largely from organic compounds. They form the molecular foundation of life.
These compounds can vary immensely, ranging from simple molecules, like methane ( CH_4 ), to complex structures like proteins and DNA. The study of organic compounds involves understanding how carbon atoms can be arranged and rearranged, leading to an endless variety of structures, each with unique properties and reactivities.
The exercise, which involved 1-chloro-3-methylpentane, showcases a typical alkane-based organic compound with a halogen substituent, in this case, chlorine. Recognizing such structures, with their functional groups, is essential for predicting behavior and reactivity in chemical reactions.

Structure Identification

Structure identification is a critical skill in chemistry, especially when identifying chiral centers or functional groups, as demonstrated in the exercise with 1-chloro-3-methylpentane. This process usually starts by understanding the molecular formula and using it to visualize the compound's 3D structure.
Through visualization, we can then assess the geometric arrangement of atoms and identify features such as chiral centers, double bonds, and functional groups. This not only helps in determining the number of stereoisomers, which follow a predictable pattern defined by the formula \(2^n\) where \(n\) is the number of chiral centers, but also aids in predicting how the compound might behave in chemical reactions.
Furthermore, structure identification assists in understanding the molecule's potential interactions with other molecules, which is especially important in fields like pharmaceuticals, where different stereoisomers of a compound can have drastically different effects on the body.