Problem 35 - A Complete Resource Book in Chemistry for JEE Main

Question

When an ether is exposed to air for sometime, an explosive substance is produced which is (a) TNT (b) super oxide (c) oxide (d) peroxide

Step-by-Step Solution

Answer

(d) Peroxide

Step 1: Identify the Ether Reaction with Air

When ethers are exposed to air, they tend to react with oxygen present in the air. This reaction is a slow process but becomes significant over time. The ethers react with oxygen to form a new compound.

Step 2: Determine the Type of Compound Formed

Through the reaction of ethers with oxygen, peroxides are often formed. These peroxides are unstable and can become explosive when concentrated, which is why they pose a risk.

Step 3: Review the Options Given

The options provided are: (a) TNT, (b) super oxide, (c) oxide, and (d) peroxide. Since ethers form peroxides when exposed to air for an extended period, we can determine which option is correct.

Key Concepts

Ether Chemistry

Ethers are a fascinating group of organic compounds that consist of an oxygen atom connected to two alkyl or aryl groups. This structure can be represented by the general formula \( R-O-R' \). Ethers' simple structure and properties lead them to be highly utilized in laboratories as solvents. However, they have a few properties that require careful attention.

A key characteristic of ethers is their relatively low chemical reactivity compared to alcohols. This is due, in large part, to the absence of the OH group seen in alcohols. Despite this low reactivity, ethers are not entirely inert. They are prone to oxidation, particularly when left open to air for prolonged periods. This tendency to react with oxygen is at the heart of why they can form potentially hazardous compounds.

Furthermore, the properties of ethers, such as low polarity and high boiling points, make them unique and useful solvents in organic chemistry. But it also means they can unknowingly become a source of risk if not stored correctly.

Peroxides Formation

When ethers are left exposed to the air, a slow reaction occurs between the ether molecules and oxygen. This reaction can lead to the formation of peroxide compounds. Peroxides are created when an oxygen molecule (O\(_2\)) interacts with the ether's electron clouds. The end result is often an organic peroxide.

Peroxide formation is particularly common in ethers with easily accessible hydrogen atoms, such as diethyl ether. As the concentration of formed peroxide increases, the compound becomes more unstable. This instability is concerning because concentrated peroxides can detonate with minimal external stimulus, leading to potential explosions.

There are certain conditions that favor peroxide formation:

• Prolonged exposure to air
• Light and heat
• Presence of specific metal ions

The guidelines commonly recommend inhibitors or stabilizers, minimizing light exposure during storage, and ensuring airtight storage. Awareness of these factors and taking proactive measures can help prevent dangerous situations involving ethers.

Chemical Safety

In chemical laboratories, safety cannot be overstated, particularly when dealing with unstable substances such as peroxides. Being aware of the dangers and understanding proper handling and storage are paramount.

To prevent peroxide formation in ethers, it is advisable to:

• Store ethers in completely sealed containers, ideally with nitrogen or another inert gas to limit exposure to oxygen.
• Regularly test long-stored ethers for peroxide presence, using commercial test strips or kits.
• Avoid storing ethers in clear glass bottles or under bright light.

Should you confirm the presence of peroxides, expert advice is vital before deciding on dilution or disposal. Additionally, understanding the proper usage and handling of ethers needs reiteration during training and lab preparations.

All personnel working with ethers should have thorough grounding in recognized safety procedures. This prepares them for the double assurance of using protective equipment and implementing strict storage controls. Maintaining a sense of vigilance against potential hazards is integral to safe practice in any environment where ethers and possible peroxides are involved.