Question

Which of the following statement is false? (1) In a conjugate pair of reduetant and oxidant the reductant has lowest oxidation number. (2) In a conjugate pair of reductant and oxidant the oxidant has higher oxidation number. (3) When an clement is oxidiscd its oxidation number increases. (4) In the reaction with lithium, hydrogen is oxidised.

Short answer

Statement 4 is false.

Step-by-step solution

Identify the statements for truthfulness

Examine each statement individually to determine its truthfulness based on oxidation and reduction principles.

Evaluate Statement 1

Statement 1: In a conjugate pair of reductant and oxidant, the reductant has the lowest oxidation number. This is true because the reductant donates electrons, thus having a lower oxidation state.

Evaluate Statement 2

Statement 2: In a conjugate pair of reductant and oxidant, the oxidant has a higher oxidation number. This is true because the oxidant accepts electrons, thus having a higher oxidation state.

Evaluate Statement 3

Statement 3: When an element is oxidized its oxidation number increases. This is true because oxidation involves the loss of electrons, resulting in an increase in oxidation number.

Evaluate Statement 4

Statement 4: In the reaction with lithium, hydrogen is oxidized. This is false because lithium is more reactive than hydrogen and typically reduces hydrogen (i.e., hydrogen gains electrons and becomes reduced).

Determine the false statement

Based on the evaluations, Statement 4 is the false one.

Key concepts

oxidation number

Understanding oxidation numbers is crucial in analyzing redox reactions. An oxidation number is a value assigned to an element in a chemical compound that indicates the number of electrons lost or gained by an atom. Here are key points to remember:

• Oxidation numbers are assigned based on a set of rules, such as hydrogen almost always being +1 and oxygen almost always being -2.
• In their natural states, elements have an oxidation number of 0.
• Oxidation involves the increase in oxidation number, while reduction involves the decrease in oxidation number.

These numbers help track the electron transfer process in redox reactions, making it easier to identify which elements are oxidized and which are reduced.

conjugate pairs

Conjugate pairs in redox reactions refer to the relationship between a reductant (reducing agent) and an oxidant (oxidizing agent).

• The reductant is the species that donates electrons and is itself oxidized.
• The oxidant is the species that accepts electrons and is itself reduced.
• In a conjugate pair, the reductant has a lower oxidation number initially; after oxidation, it forms the conjugate oxidant with a higher oxidation number.
• Conversely, the oxidant starts with a higher oxidation number and after reduction, it forms the conjugate reductant with a lower oxidation number.

This relationship is fundamental in understanding how substances undergo changes during redox reactions.

redox reactions

Redox reactions, short for reduction-oxidation reactions, involve the transfer of electrons between two species. These reactions are characterized by the change in oxidation numbers of the reacting elements.

• Oxidation describes the loss of electrons by a molecule, atom, or ion.
• Reduction describes the gain of electrons by a molecule, atom, or ion.
• These processes occur simultaneously: while one species is oxidized, another is reduced.
• Redox reactions are common in various processes, including combustion, respiration, and even photosynthesis.

By understanding redox reactions, you can better grasp how electrons are transferred and how energy interchange occurs in chemical processes.

electron transfer

The core of redox reactions is the transfer of electrons from one substance to another. Here's a deeper look into this process:

• Electrons move from the reductant (higher energy state) to the oxidant (lower energy state).
• The substance losing electrons is said to be oxidized, and its oxidation state increases.
• The substance gaining electrons is said to be reduced, and its oxidation state decreases.
• Electron transfer is crucial in many biological and chemical systems, playing a key role in energy production and conversion.

By tracking electron flow, you can predict the outcomes of redox reactions and understand the mechanisms driving these chemical changes.