Among the following forms of carbon and carbon-rich materials, which is considered the most pure form of elemental carbon?

Introduction / Context:
Carbon occurs in nature in several allotropic forms and in many carbon-rich materials such as different types of coal and charcoal. The degree of purity of carbon in these forms varies widely, depending on the presence of other elements and the structure of the carbon itself. This question asks you to identify which of the listed substances is the most pure form of elemental carbon, highlighting the distinction between true allotropes and carbon-containing mixtures like coal.

Given Data / Assumptions:

• The options are anthracite, lampblack, graphite, and wood charcoal.
• Anthracite is the highest grade of coal.
• Lampblack is a form of amorphous carbon obtained from incomplete combustion.
• Graphite is a crystalline allotrope of carbon.
• Wood charcoal is produced by heating wood in limited air and contains carbon plus some impurities.

Concept / Approach:
Anthracite is a very high carbon coal but still contains other substances such as moisture, volatile matter, and mineral impurities; it is not pure carbon. Wood charcoal is also mostly carbon but retains some inorganic ash and trapped gases. Lampblack is a fine form of amorphous carbon produced by incomplete combustion of hydrocarbons, yet it too can contain traces of hydrogen and other impurities. Graphite, on the other hand, is an allotrope of carbon in which atoms are arranged in layers of hexagonal lattices. As an allotrope, it is composed of carbon atoms only and is considered a pure form of carbon, like diamond. Therefore, among the options, graphite is the most pure form of elemental carbon.

Step-by-Step Solution:
Step 1: Consider anthracite. Anthracite has a high percentage of carbon compared to other coals but still contains noncarbon impurities and is not a pure element. Step 2: Consider lampblack. Lampblack is a soot-like amorphous carbon; although rich in carbon, it may contain hydrogen and other impurities. Step 3: Consider wood charcoal. Wood charcoal is obtained from wood and contains carbon plus ash and other inorganic residues. Step 4: Consider graphite. Graphite is a crystalline allotrope consisting of layers of pure carbon atoms arranged in hexagonal patterns. Step 5: Conclude that graphite, being an elemental allotrope, is the most pure form of carbon among the given choices.

Verification / Alternative check:
In discussions of carbon allotropes, both diamond and graphite are emphasised as pure forms of carbon with different structures and properties. Coal, charcoal, and lampblack are described as forms of amorphous carbon but also as mixtures with varying amounts of noncarbon materials. Analytical measurements show that even high grade anthracite may contain several percent of other substances, whereas ideal graphite is purely carbon. This distinction is reflected in exam oriented material that often asks which is the purest form of carbon; when diamond is not among the options, graphite is typically the correct one, especially when compared with coal or charcoal derivatives.

Why Other Options Are Wrong:
Option A (Anthracite): Although it is the purest variety of coal with high carbon content, it still contains noncarbon impurities and is not an elemental allotrope. Option B (Lampblack): Lampblack is largely carbon but is an amorphous product of incomplete combustion and may contain other elements. Option D (Wood Charcoal): Charcoal contains carbon plus ash and other residual components from the original wood.

Common Pitfalls:
Students sometimes confuse “purest form of coal” with “purest form of carbon”. Anthracite is indeed the purest coal but not the purest elemental carbon. Another confusion is treating all black, carbon-rich materials as equally pure carbon. To avoid these mistakes, remember that allotropes like diamond and graphite are structurally pure forms of the element, while coal and charcoal are natural mixtures with varying compositions. When diamond is missing from the options and graphite appears alongside coal-like materials, graphite is typically the correct answer.

Final Answer:
The most pure form of carbon among the given options is Graphite.