Question

Which of the following statements is falsc? (1) Diamond and graphitc have different lattice structures. (2) Diamond is the purest form and graphite is the impurc form of carbon. (3) Diamond can be used as an abrasive while graphite can be used as a lubricant. (4) Both on burning in air give \(\mathrm{CO}_{2}\).

Short answer

Statement (2) is false.

Step-by-step solution

Identify the Statements

There are four statements provided about diamond and graphite. The goal is to determine which statement is false.

Examine Statement 1

Statement: 'Diamond and graphite have different lattice structures.' This statement is true because diamond has a tetrahedral lattice structure while graphite has a planar hexagonal lattice structure.

Examine Statement 2

Statement: 'Diamond is the purest form and graphite is the impure form of carbon.' This statement is false. Both diamond and graphite are pure forms of carbon; graphite is not an impure form.

Examine Statement 3

Statement: 'Diamond can be used as an abrasive while graphite can be used as a lubricant.' This statement is true. Diamond's hardness makes it suitable for abrasive uses, while the slippery layers of graphite make it a good lubricant.

Examine Statement 4

Statement: 'Both on burning in air give \(\text{CO}_{2}\).' This statement is true. When both diamond and graphite burn in oxygen, they produce carbon dioxide.

Determination of False Statement

After evaluating all four statements, it can be concluded that statement (2) is false.

Key concepts

lattice structures

Diamond and graphite exhibit different lattice structures, which are key to their distinct properties. The lattice structure of a diamond is tetrahedral, meaning each carbon atom is bonded to four other carbon atoms in a three-dimensional framework. This gives diamond its extraordinary hardness and high melting point. Graphite, on the other hand, has a planar hexagonal lattice structure. In graphite, each carbon atom is bonded to three other carbon atoms in flat, two-dimensional layers. These layers are loosely held together by weak van der Waals forces, allowing them to slide over one another and making graphite slippery and soft. The different lattice structures of diamond and graphite lead to their unique physical properties and uses. Diamonds are used for cutting and grinding due to their hardness, while graphite is used as a lubricant and in pencils.

purity of carbon forms

Both diamond and graphite are pure forms of carbon, each composed of only carbon atoms. The misconception that graphite is an impure form of carbon likely arises from its common mixture with other materials in everyday objects, such as the 'lead' in pencils, which is actually a mix of graphite and clay. However, in their basic forms, both materials are simply different structural arrangements of carbon. The purity of these carbon forms is crucial in industrial applications where specific properties, like high thermal conductivity or electrical conductivity, are needed. In research and technology, high-purity graphite and diamonds are used to achieve precise results and high-performance outcomes.

uses of diamond and graphite

The distinct properties of diamond and graphite dictate their various uses. Diamonds are renowned for their hardness and optical properties. They are used in cutting, grinding, and drilling tools. Additionally, their brilliance and light dispersion make them highly valued in jewelry. Graphite, with its layered structure and softness, is employed as a lubricant in machinery and as a material in pencils. Graphite is also used in batteries, electrodes, and as a moderator in nuclear reactors due to its high conductivity and ability to withstand high temperatures. Each use of diamond and graphite exploits their unique structural features.

combustion of carbon allotropes

When diamond and graphite burn, they both react with oxygen to form carbon dioxide (\text{CO}_{2}\text{CO}_{2}). This process is known as combustion. Despite their different structures, both materials are made up of carbon, and thus, their combustion results in the release of the same gaseous by-product. This reaction can be represented by the chemical equation: \ \[C (s) + O_{2} (g) \rightarrow CO_{2} (g)\] The energy released during the combustion of diamond and graphite can be different because of their different structures, but the end product, carbon dioxide, remains the same. This illustrates that at a fundamental level, diamond and graphite share the same chemical composition.