Question

Reductants are substances which (1) Show increase in their oxidation number during a change. (2) Lose electrons during a change. (3) Reduce other and oxidise themsclves. (4) All.

Short answer

(4) All

Step-by-step solution

Understand the Definition of Reductants

Reductants, or reducing agents, are substances that lose electrons in a chemical reaction and, as a result, oxidize themselves. They donate electrons to another substance, reducing it.

Examine the Statements

Review each statement provided in the question:(1) Increase in oxidation number.(2) Lose electrons during a change.(3) Reduce others and oxidize themselves.(4) All.

Analyze Each Statement

Compare each statement with the definition of a reductant:- (1) A reductant does show an increase in its oxidation number because it loses electrons.- (2) A reductant does lose electrons during the reaction.- (3) A reductant reduces other substances and oxidizes itself.

Determine the Correct Answer

Considering the analysis, all provided statements (1), (2), and (3) are true for reductants. Therefore, the correct answer is (4) All.

Key concepts

Oxidation Number

Let's dive into the concept of oxidation number. It's a value assigned to an element in a chemical compound. This number represents how many electrons an atom gains, loses, or appears to use when forming compounds.

Oxidation number can seem tricky, but here's a simple way to think about it. Imagine it's a sort of score for electrons. Elements can have positive, negative, or neutral oxidation numbers.

Here’s a clear rule of thumb:

• If an atom loses electrons, its oxidation number increases.
• If an atom gains electrons, its oxidation number decreases.

This rule is crucial when looking at redox (reduction-oxidation) reactions. These reactions involve changes in oxidation numbers. Understanding how these changes work is key to grasping the concept of reductants.

Losing Electrons

Now, let’s focus on the idea of losing electrons. In chemistry, when a substance loses electrons, we say it’s being oxidized.

It may help to think of electrons as being really tiny particles with a bit of a negative charge. If something loses these particles, it actually becomes more positive.

Here’s an easy-to-remember point:

• Loss of electrons = Oxidation
• Gain of electrons = Reduction

So, when a reductant (reducing agent) loses electrons, it undergoes oxidation. It causes another substance to gain those electrons, hence reducing the latter. This process shows the elegant relationship between losing and gaining electrons in chemical reactions.

Reducing Agents

Reducing agents play a stellar role in chemistry. They are substances that donate electrons to other substances. During this electron donation, they reduce the other substances and, in turn, get oxidized themselves.

Think of reducing agents as generous givers. They give away their electrons freely. By doing so:

• They help other substances (known as oxidizing agents) gain electrons.
• They undergo oxidation, increasing their own oxidation state.

A good way to remember this is by associating the reducing agent with reduction. Although it sounds backwards, the reducing agent itself gets oxidized. This understanding ties together oxidation numbers, losing electrons, and the role of reducing agents in a clear, connected way.