NIOS Class 10 Science Activity 28.1 Solution | Carbon and its Compounds

In NIOS Class 10 Science Chapter 28 - Carbon and its Compounds, Activity 28.1, we compare different forms of carbon: graphite, coal, and charcoal. This activity helps us understand how the same element can exist in different forms with different properties. We also learn how carbon black is formed by heating hydrocarbons in a limited supply of oxygen.

Carbon and Its Compounds Activity Solution

This activity is based on the NIOS Class 10 science and technology (212) Chapter 28- Carbon and its Compounds Module 6- Natural Resources.To understand where these carbon resources like coal are found in India, check out our detailed solution of  activity 28.2 (coal, petroleum and natural gas)

 

NIOS Class 10 Science Activity 28.1

Aim

To compare the physical properties of graphite, coal and charcoal and understand the formation of carbon black.

Materials Required

    1. Sample of graphite

    2. Coal

   3. Charcoal

   4. White paper

   5. Magnifying glass

Procedure

We take small samples of graphite, coal and charcoal and observe their colour, texture and appearance carefully. Now we rub each sample on a piece of white paper and check whether they leave any mark or streak.

We also felt the hardness and softness of each sample and noted down all observations in a table.

Observation

Substance	Colour	texture	Mark on paper	hardness
Graphite	Black/grey	Smooth	Leaves a black mark	Soft
Coal	Black	Rough	Leaves a little mark	Hard
Charcoal	Black	brittle	Leaves a black mark	soft

 

Explanation

Graphite, coal and charcoal are forms of carbon but have different structures. Graphite has a layered structure, so it is soft and slippery and used in pencils.

Coal is a complex mixture and is harder, so it does not leave marks easily.

Charcoal is porous and soft, so it easily leaves marks on paper.

Carbon black formation

When hydrocarbons like methane is burnt in limited oxygen (incomplete combustion), carbon black (soot) is formed.

  CH₄ + O₂ → C + 2H₂O

Conclusion

We can conclude that

i.     Carbon exists in different forms with different properties; these different forms are called allotropes of carbon.

ii.  Graphite, coal and charcoal differ in hardness and texture.

iii.  Carbon black is formed due to the incomplete combustion of hydrocarbons.

Frequently Asked Questions

Q1. Why does graphite leave marks on paper?

Answer – Graphite is soft and layered and slides easily, so it leaves marks on paper.

Q2. Why is charcoal porous?

Answer – Charcoal is formed by heating wood without air, so tiny pores are formed in it, which is why it is porous.

Q3. What is carbon black?

Answer – A fine black powder of carbon formed by the incomplete burning of hydrocarbons.

Q4. Why does coal not leave marks easily?

Answer- Coal is hard.

Q5. What is incomplete combustion?

Answer – The burning in limited oxygen is called incomplete combustion.

Multiple Choice Questions

Q1. Which form of carbon is soft and slippery?

(a)       Coal

(b)      Charcoal

(c)       Graphite

(d)      None of these

Correct answer – ( c) – graphite

Q2. Which form of carbon is porous in nature?

(a)       Graphite

(b)      Coal

(c)       Charcoal

(d)      Diamond

Correct answer –(c) - Charcoal

Q3. Carbon black is formed due to:

(a)       Complete combustion

(b)      Incomplete combustion

(c)       Oxidation

(d)      Reduction

Correct answer – (b) – Incomplete combustion

Q4. Which substance is the hardest among the following:

(a)       Graphite

(b)      Coal

(c)       Charcoal

(d)      Carbon black

Correct answer- (b)- Coal

Q5. The reaction CH₄ + O₂ → C + 2H₂O shows:

(a)       Complete combustion

(b)      Incomplete combustion

(c)       Decomposition

(d)      Neutralisation

Correct answer – (b) -     Incomplete combustion