Question

The product formed when isopropyl alcohol is heated with a suspension of bleaching powder in water is (a) propyne (b) 2 - chloropropane (c) chloroform (d) carbon tetrachloride

Short answer

Answer: The product formed in this reaction is 2-chloropropane.

Step-by-step solution

Write down the reaction of isopropyl alcohol with bleaching powder

First, let's write the chemical formula of isopropyl alcohol and bleaching powder. Isopropyl alcohol (or 2-propanol) has the chemical formula \(\mathrm{CH_3CH(OH)CH_3}\), and bleaching powder (or calcium hypochlorite) has the chemical formula \(\mathrm{Ca(OCl)_2}\). When an alcohol reacts with a hypohalite (like in a bleaching powder), it generally forms a haloalkane. In this case, we would expect the product to be a chloroalkane.

Determine the product of the reaction

As mentioned earlier, the product of the reaction is expected to be a chloroalkane. Let's consider the possible products and compare them to the given answer choices: (a) Propyne -- This is a product of dehydrohalogenation (elimination), which is not expected in this reaction. So, this answer can be discarded. (b) 2-chloropropane -- This is a possible product as the hydroxyl group of isopropyl alcohol in the reaction has been replaced by a chlorine atom. \(\mathrm{CH_3CH(OH)CH_3 + Ca(OCl)_2 \rightarrow CH_3CH(Cl)CH_3}\). (c) Chloroform -- This can be formed in the reaction of ethanol with bleaching powder, but not in this case, as there is no hydrogen atom in the alpha position of isopropyl alcohol. (d) Carbon tetrachloride -- This is not formed in the reaction of alcohols with bleaching powder.

Choose the correct answer

From the analysis above, we find that the correct product of the reaction between isopropyl alcohol and bleaching powder is 2-chloropropane. Therefore, the correct answer is (b) 2-chloropropane.

Key concepts

Understanding Isopropyl Alcohol

Isopropyl alcohol, also known as 2-propanol, plays a significant role in organic chemistry and is commonly used in laboratories. Its structure is represented by the chemical formula \(\mathrm{CH_3CH(OH)CH_3}\). One of its hydrogens is bonded to an oxygen atom, forming a functional group known as a hydroxyl group (OH). This functional group is responsible for many of isopropyl alcohol's reactions with other chemicals, including its interaction with bleaching powder.

Isopropyl alcohol is used in various applications such as cleaning, disinfecting, and as a solvent due to its ability to dissolve a wide range of non-polar compounds. It is also interesting to note that isopropyl alcohol can be dehydrated to produce propene or oxidized to give acetone, showcasing its versatility in chemical reactions.

For students tackling problems in organic chemistry, understanding the structure and reactivity of isopropyl alcohol is crucial, as it forms the basis for many synthesis reactions and can be transformed into multiple products under different conditions.

Bleaching Powder Reactions

Bleaching powder, chemically known as calcium hypochlorite \(\mathrm{Ca(OCl)_2}\), is used for bleaching and as a disinfectant. When mixed with water, it releases chlorine, which is responsible for its bleaching and germicidal effects. The chemistry behind bleaching powder involves hypochlorous acid \(\mathrm{HOCl}\), which forms when bleaching powder reacts with water. This acid is a strong oxidizing agent, and it can react with various organic and inorganic substances, such as alcohols, to form haloalkanes.

In organic synthesis, this oxidation property is applied to transform alcohols into chloro-compounds, among other products. For IIT JEE aspirants, understanding these reactions is important as it forms a basis for questions on functional group transformations, a recurrent theme in the examination. Comprehension of bleaching powder's reactivity with alcohols, like isopropyl alcohol, helps in prediction and identification of products in synthesis problems.

Chloroalkane Synthesis

Chloroalkanes, also known as alkyl halides, are a class of organic compounds where at least one halogen atom is substituted for a hydrogen in an alkane. Synthesizing chloroalkanes typically involves the substitution of a hydroxyl group in an alcohol with a chlorine atom via a reaction with halogenating agents, such as hydrochloric acid or bleaching powder.

In the context of the reaction between isopropyl alcohol and bleaching powder, we observe a substitution reaction where the -OH group in isopropyl alcohol is replaced by a chlorine atom, yielding 2-chloropropane as the product. This type of reaction is a common method to synthesize chloroalkanes and is an essential concept in organic chemistry for IIT JEE preparation.

Understanding the mechanistic pathway of how alcohols are transformed into chloroalkanes, as well as the conditions required for these transformations, can greatly assist students in solving complex problems that require knowledge of organic synthesis routes. Moreover, such knowledge lays the foundation for grasping more intricate organic reactions that students may encounter in their academic and professional careers in chemistry.