Problem 31 - A Complete Resource Book in Chemistry for JEE Main

Question

Which among these is a hypnotic drug? (a) metaldehyde (b) acetaldehyde (c) paraldehyde (d) none of these

Step-by-Step Solution

Answer

(c) paraldehyde is a hypnotic drug.

Step 1: Understanding the Options

First, let's clarify what each term represents. Metaldehyde (a) is commonly used as a pesticide; acetaldehyde (b) is an organic compound used in the production of acetic acid and perfumes; paraldehyde (c) is a chemical compound formed by the polymerization of acetaldehyde and has different medical uses. 'None of these' (d) suggests that none of the options is a hypnotic drug.

Step 2: Identifying Hypnotic Drugs

A hypnotic drug is one that induces sleep or sedation. Hypnotics are a class of drugs that tend to produce sleep or sedate, primarily in the treatment of insomnia.

Step 3: Matching Options to Hypnotic Criteria

We need to match the options against the hypnotic criteria. Paraldehyde (c) is known for its sedative and hypnotic properties and has been used in the past as a sedative for psychiatric patients. Metaldehyde and acetaldehyde are not used as hypnotics.

Step 4: Selecting the Correct Answer

Based on our analysis, paraldehyde (c) fits the description of a hypnotic drug due to its sedative effects, whereas the others do not.

Key Concepts

Metaldehyde

Metaldehyde is a chemical compound primarily used as a pesticide. It is most commonly found as a molluscicide, a substance used to control or kill slugs and snails that harm plants. Due to its widespread use in gardens and agriculture, it's important to understand its potential effects. Metaldehyde works by disrupting the mucous trails that slugs and snails produce, which dehydrates these creatures, eventually killing them. The compound is usually found in pellet form when used as a pest control tool.

Although it is effective in pest control, metaldehyde is toxic to both humans and animals if ingested. Caution is advised when using this chemical around pets and children. Importantly, metaldehyde is not a hypnotic drug. It lacks any properties that would induce sleep or sedation in humans.

Acetaldehyde

Acetaldehyde is a simple organic compound that is an intermediate in the production of various chemicals. It is a volatile, flammable liquid that plays a significant role in industrial chemistry. Acetaldehyde is pivotal in the production of acetic acid, which is a key component in the manufacture of numerous products such as synthetic vinegar and perfumes.

Aside from industrial uses, acetaldehyde is also naturally present in some foods and is produced within the body as it metabolizes alcohol. One interesting aspect of acetaldehyde is its connection to the sensations some people experience as a "hangover," due to its accumulation during alcohol consumption. However, it is important to note that acetaldehyde is not used as a hypnotic. It simply doesn't have the properties needed to induce sleep or sedation.

Paraldehyde

Paraldehyde is a chemical compound that emerges from the polymerization of acetaldehyde. It holds a unique place in both industrial and medical applications. One of its most notable uses was as a sedative and hypnotic drug. Historically, paraldehyde has been used to calm psychiatric patients and treat conditions like acute agitation and delirium. It was recognized for its ability to induce sleep without depressing the respiratory system, a beneficial trait for a sedative.

Despite its historical use in medicine, the role of paraldehyde has diminished with the development of newer drugs that offer better efficacy and safety profiles. Still, its hypnotic properties make it a substance of interest when studying the history of medical treatments for insomnia and other related conditions.