Question

What is the correct sequence of coal types from lowest to highest carbon content?

• A. Lignite $\rightarrow$ Peat $\rightarrow$ Bituminous $\rightarrow$ Anthracite
• B. Peat $\rightarrow$ Lignite $\rightarrow$ Bituminous $\rightarrow$ Anthracite
• C. Peat $\rightarrow$ Bituminous $\rightarrow$ Lignite $\rightarrow$ Anthracite
• D. Lignite $\rightarrow$ Bituminous $\rightarrow$ Peat $\rightarrow$ Anthracite

Hint:

A simple way to remember the sequence of coal types: \textbf{Peat $\rightarrow$ Lignite $\rightarrow$ Bituminous $\rightarrow$ Anthracite} You can remember it using the mnemonic: \textbf{``Please Learn Basic Analysis''} (Peat, Lignite, Bituminous, Anthracite) Carbon content and heating value increase in this order.

Answer 1

The Correct Option is B

Concept: Coal is a fossil fuel formed from the remains of plants that lived millions of years ago. Over long geological periods, these plant remains were buried under layers of sediments and subjected to high pressure and temperature. This process gradually converted the plant material into different types of coal. The transformation of plant material into coal is known as coalification. During coalification, the carbon content increases, while moisture and volatile substances decrease. As a result, coal types are classified based on their carbon percentage and calorific value. The major types of coal in increasing order of carbon content are:

• Peat
• Lignite
• Bituminous
• Anthracite

Each successive stage contains a higher percentage of carbon and produces more heat when burned.
Step 1: Understanding the stages of coal formation.
Coal formation occurs in stages as pressure and temperature increase over time:

• Peat: This is the earliest stage of coal formation. It contains the lowest carbon content and a high amount of moisture. Peat is partially decayed plant material.
• Lignite: Also called \textit{brown coal}. It contains more carbon than peat but still has relatively high moisture content.
• Bituminous Coal: This is the most widely used type of coal. It has higher carbon content and greater heating value than lignite.
• Anthracite: This is the highest quality coal with the maximum carbon content and the highest calorific value. It burns with a clean, smokeless flame.

Step 2: Arranging coal types in increasing carbon content.
From lowest to highest carbon percentage: \[ \text{Peat} \rightarrow \text{Lignite} \rightarrow \text{Bituminous} \rightarrow \text{Anthracite} \] Thus, the correct sequence is: \[ \boxed{\text{Peat} \rightarrow \text{Lignite} \rightarrow \text{Bituminous} \rightarrow \text{Anthracite}} \]
Step 3: Checking the given options.
Among the given options, option (B) correctly represents the increasing order of carbon content in coal types.