Question

How many chiral carbons are in 4 -bromo- 2 -chloro-2butanol? \((\mathbf{a}) 0,(\mathbf{b}) 1,(\mathbf{c}) 2,(\mathbf{d}) 3,(\mathbf{e}) 4\) or more.

Short answer

Answer: \(\mathbf{(b)}\) 1 chiral carbon.

Step-by-step solution

Draw the structure of 4-bromo-2-chloro-2-butanol

To draw the structure, we begin with the parent chain of 4 carbons (butane) and then add the functional groups at the specified positions: 4-bromo, 2-chloro, and 2-butanol. The structure will look like this: H H Cl OH Br | | | | | C-C-C-C | | | | H H H Br

Identify chiral carbons

Now that we have the structure, we need to examine each carbon atom to determine whether it is chiral or not. To be chiral, a carbon must be bonded to four different groups. Carbon 1 (C1): bonded to 3 hydrogens and C2. Not chiral. Carbon 2 (C2): bonded to C1, C3, a chlorine atom, and a hydroxyl (OH) group. Chiral. Carbon 3 (C3): bonded to C2, C4, and 2 hydrogens. Not chiral. Carbon 4 (C4): bonded to C3, a bromine atom, and 2 hydrogens. Not chiral.

Determine the number of chiral carbons

From our previous analysis, we found that only carbon 2 (C2) is chiral in the compound 4-bromo-2-chloro-2-butanol.

Choose the correct answer

Since we found only 1 chiral carbon, the correct answer is: Answer: \(\mathbf{(b)}\) 1 chiral carbon.

Key concepts

4-bromo-2-chloro-2-butanol

4-bromo-2-chloro-2-butanol is an interesting chemical compound in organic chemistry. To understand it better, let's break down its name. The name might sound complex, but it's just a way to describe how the compound is structured.

The 'butanol' part of the name tells us that the main chain of the molecule is derived from butane, meaning it has four carbon atoms connected in a sequence. The numbers '4' and '2' indicate the positions on the carbon chain where additional groups are attached.

Specifically, at the carbon in the fourth position, a bromine atom (bromo) is attached, and at the second carbon, both a chlorine atom (chloro) and an OH group (making it an alcohol) are attached. The full name explains the structure: a four-carbon molecule with substitutions that make it both an alcohol and a halogenated compound.

Chiral Center Identification

Identifying chiral centers is a fundamental skill in organic chemistry, especially when analyzing molecules like 4-bromo-2-chloro-2-butanol.

A chiral center is a carbon atom that is attached to four different groups. This unique structure means there is no symmetry and the molecule cannot be superimposed on its mirror image, making it chiral. Think of your hands: they are mirror images but cannot be perfectly overlaid.

In the case of 4-bromo-2-chloro-2-butanol, we look at each carbon atom to see if it satisfies this condition:

• Carbon 1 (C1) is bonded to 3 hydrogen atoms and another carbon atom, so it is not chiral.
• Carbon 2 (C2) is bonded to four different groups - a chlorine, a hydrogen, a hydroxyl group, and a carbon - making it chiral.
• Carbon 3 (C3) and carbon 4 (C4) do not meet the criteria as they do not have four distinct attachments.

Chiral centers are crucial because they often affect the molecule's chemical behavior and biological activity.

Organic Chemistry

Organic chemistry is a branch of chemistry that deals with structures, properties, and reactions of organic compounds, which mainly consist of carbon and hydrogen. It is vital in understanding life processes and in the development of new materials.

The beauty of organic chemistry lies in its vast diversity due to carbon's ability to form stable bonds with many elements, including itself. This capability gives rise to an incredible variety of compounds, including simple hydrocarbons to complex biomolecules like DNA.

Understanding organic chemistry is essential for predicting how molecules like 4-bromo-2-chloro-2-butanol behave. It helps in deducing reactivity patterns, physical properties, and potential synthetic routes. Additionally, concepts like chirality have vast implications in pharmacology, materials science, and stereochemistry, highlighting the real-world applications of organic chemistry.