Question

Heterolysis of propane gives (1) Methyl and ethyl frec radicals (2) Methylium cation and cthyl anion (3) Mcthyl anion and cthylium cation (4) Mcthylium and cthylium cations

Short answer

The correct answer is (2) Methylium cation and ethyl anion.

Step-by-step solution

Understand Heterolysis

Heterolysis is the process by which a chemical bond is broken asymmetrically, resulting in one fragment carrying the shared pair of electrons as a lone pair.

Identify Propane Structure

Propane has the chemical formula \({C_3H_8}\). Its structure consists of a chain of three carbon atoms, with each carbon bonded to enough hydrogen atoms to complete its four bonds.

Predict the Bond Cleavage

In the context of heterolysis, consider which bond within the propane can be broken to yield a significant cation and anion pair. Typically, the cleavage will occur between a carbon-carbon bond.

Analyze Possible Ion Pairs

When a carbon-carbon bond in propane breaks heterolytically, one fragment will take both electrons from the bond, forming an anion, and the other fragment will form a cation. For example, the cleavage of the bond between the first and second carbon atoms would yield a methylium cation (\({CH_3^+}\)) and an ethyl anion (\({C_2H_5^-}\)).

Verify the Result

Check the provided options against the predicted ion pairs to find the correct answer. The correct result is the formation of a methylium cation and an ethyl anion.

Key concepts

chemical bond cleavage

When discussing chemical reactions, it's essential to understand the concept of bond cleavage. In heterolysis, chemical bond cleavage occurs asymmetrically. This means that when a bond breaks, the shared pair of electrons isn't split evenly.
Instead, one of the resulting fragments takes both electrons, leaving the other fragment without. This process is crucial in many organic chemistry reactions.

For propane, this kind of bond cleavage usually happens between carbon atoms. This is because carbon-carbon bonds, though stable, can be broken under specific conditions to yield new reactive species. By understanding bond cleavage, we can predict and explain the formation of ions in various chemical reactions.

carbon-carbon bond

Propane (C3H8) consists of a chain of three carbon atoms. Each carbon atom forms bonds with hydrogen atoms to fulfill its tetravalency (four bonds per carbon atom).
In the context of heterolysis, the carbon-carbon bond breaking is particularly interesting.

When a carbon-carbon bond in propane breaks heterolytically, it means one carbon atom will take both bonding electrons, while the other gets none. This process results in the formation of ions. Breaking a C-C bond in propane can lead to the production of significant ion pairs, such as a methylium cation (CH3+) and an ethyl anion (C2H5-).
This understanding helps chemists predict the behavior of organic compounds under different conditions.

cation and anion formation

The breaking of chemical bonds in heterolysis leads to the creation of ions. A cation is a positively charged ion, while an anion is a negatively charged ion.
In the case of propane’s heterolysis, the bond between the first and second carbon atoms can be broken to yield a methylium cation (CH3+) and an ethyl anion (C2H5-).

This happens because the electrons in the bond migrate to one of the carbon atoms fully, leaving the other carbon atom electron-deficient. The carbon atom that takes both electrons becomes negatively charged (anion).
Conversely, the carbon atom left without electrons becomes positively charged (cation). Such ion formations are essential in many reactions, especially in organic chemistry, where intermediate species like cations and anions play crucial roles in reaction mechanisms.