CBSE Class 11 Geography: Minerals and Rocks NCERT Solutions

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NCERT Solutions PDF Class 11 PDF

This chapter delves into the fundamental concepts of minerals and rocks, crucial for understanding Physical Geography. The NCERT Solutions for Class 11 Geography, Chapter 5, provide clear explanations and answers to key questions. Students will learn about the composition of common rocks like granite, the distinguishing features of metamorphic rocks such as foliation, and the classification of minerals. The solutions also cover the formation and characteristics of igneous rocks, the process of sedimentary rock formation, and the dynamic rock cycle that illustrates the transformation between different rock types. These solutions are designed to help students grasp complex geological processes and prepare effectively for their examinations by offering detailed, step-by-step explanations.

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BoardCBSE
ClassClass 11
SubjectFundamental of Physical Geography
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 5

Chapter summary

Chapter 5, Minerals and Rocks, focuses on the basic building blocks of the Earth's crust. The NCERT Solutions cover multiple-choice questions on rock composition and features, and detailed answers on the definitions, formation processes, and characteristics of igneous, sedimentary, and metamorphic rocks. It also explains the interrelationship between these rock types through the rock cycle, providing a foundational understanding of geology.

Learning outcomes

  • Identify the main constituents of common rocks like granite.
  • Recognize the salient features of metamorphic rocks, such as foliation.
  • Distinguish between single element minerals and compound minerals.
  • Identify the hardest mineral.
  • Differentiate between igneous, sedimentary, and metamorphic rocks.
  • Describe the formation processes of igneous, sedimentary, and metamorphic rocks.
  • Explain the concept and significance of the rock cycle.

Topics covered

Paper topics

  • Minerals
  • Rocks
  • Granite composition
  • Metamorphic rocks
  • Foliation
  • Single element minerals
  • Hardest mineral (Diamond)
  • Sedimentary rocks
  • Igneous rocks
  • Rock cycle
  • Petrology
  • Types of rocks

Important topics

  • Definition and classification of rocks
  • Formation of igneous rocks
  • Formation of sedimentary rocks
  • Formation of metamorphic rocks
  • Characteristics of different rock types
  • The Rock Cycle
  • Minerals vs. Rocks

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Questions and Solutions

Multiple choice question

Which one of the following are the two main constituents of granite?
  1. Iron and nickel
  2. Iron and silver
  3. Silica and aluminum
  4. Iron Oxide and potassium
Solution: Granite is a common type of intrusive igneous rock. Its primary mineral composition includes quartz, feldspar, and mica. Among the given options, silica and aluminum are the most significant constituents, forming the basis of many minerals found in granite, such as silicates and aluminosilicates.

Question 1 (b)

Which one of the following is the salient feature of metamorphic rocks?
  1. Changeable
  2. Quite
  3. Crystalline
  4. Foliation
Solution: Metamorphic rocks are formed when existing rocks are transformed by heat, pressure, or chemical reactions. A key characteristic of many metamorphic rocks is foliation, which is the development of parallel alignment of mineral grains or the compositional banding within the rock, giving it a layered appearance. While metamorphic rocks can be crystalline and are formed through change, foliation is a particularly distinctive feature.

Question 1 (c)

Which one of the following is not a single element mineral?
  1. Gold
  2. Silver
  3. Mica
  4. Graphite
Solution: Single element minerals, also known as native elements, are composed of only one type of atom. Examples include Gold (Au), Silver (Ag), and Graphite (C). Mica, however, is not a single element mineral; it is a group of complex silicate minerals composed of various elements like aluminum, potassium, magnesium, and iron, in addition to silicon and oxygen.

Question 1 (d)

Which one of the following is the hardest mineral?
  1. Topaz
  2. Diamond
  3. Quartz
  4. Feldspar
Solution: The hardness of minerals is often measured using the Mohs scale. On this scale, Diamond is the hardest known natural mineral, assigned a value of 10. Topaz has a hardness of 8, Quartz has a hardness of 7, and Feldspar typically has a hardness of 6. Therefore, diamond is the hardest among the given options.

Question 1 (e)

Which one of the following is not a sedimentary rock?
  1. Tillite
  2. Borax
  3. Breccia
  4. Marble
Solution: Sedimentary rocks are formed from the accumulation and cementation of sediments. Tillite is a sedimentary rock formed from glacial deposits. Borax is a mineral often found in evaporite deposits, which are sedimentary. Breccia is a clastic sedimentary rock composed of angular fragments. Marble, however, is a metamorphic rock formed from the recrystallization of limestone or dolostone under heat and pressure.

Answer the following questions in about 30 words

Question 2 (a)

What do you mean by rocks? Name the three major classes of rocks.
Solution: Rocks are naturally occurring solid aggregates of one or more minerals or mineraloids. They constitute the solid crust of the Earth. The three major classes of rocks are igneous rocks, sedimentary rocks, and metamorphic rocks. The scientific study of rocks is called Petrology.

Question 2 (b)

What is an igneous rock? Describe the method of formation and characteristics of igneous rock.
Solution: Igneous rocks are formed from the cooling and solidification of molten rock material, known as magma (when below the Earth's surface) or lava (when erupted onto the surface). They are often called 'primary' or 'parent' rocks because all other rock types are derived from them. Characteristics include a crystalline structure, often lacking fossils, and varying textures depending on cooling rates.

Question 2 (c)

What is meant by sedimentary rock? Describe the mode of formation of sedimentary rock.
Solution: Sedimentary rocks are formed from sediments, which are fragments of pre-existing rocks, minerals, or organic matter that have been transported by agents like water, wind, or ice. These sediments are deposited in layers, and over time, they are compacted and cemented together to form solid rock. This process is called lithification.

Question 2 (d)

What relationship explained by rock cycle between the major type of rock?
Solution: The rock cycle illustrates the dynamic interrelationship and transformation processes between the three major rock types: igneous, sedimentary, and metamorphic. It shows that rocks do not remain in their original form indefinitely. For example, igneous rocks can be weathered into sediments to form sedimentary rocks, which can then be transformed into metamorphic rocks under heat and pressure. Metamorphic rocks can melt to form magma, restarting the cycle. This continuous process of change is fundamental to geology.

Common mistakes

  • Confusing the primary constituents of rocks.
  • Misidentifying the characteristic features of different rock types.
  • Not understanding the difference between single element minerals and others.
  • Incomplete understanding of the rock cycle and rock transformations.

Revision tips

  • Focus on understanding the definitions and formation processes of each rock type.
  • Memorize the key characteristics that differentiate igneous, sedimentary, and metamorphic rocks.
  • Pay close attention to the rock cycle diagram and its implications.
  • Practice identifying examples of each rock type and their constituents.

Practice MCQs

Q1. What are the two primary constituents of granite?

Q2. Which of the following is a defining characteristic of metamorphic rocks?

Q3. Which of these minerals is not a single element mineral?

Q4. According to Mohs scale, which mineral is recognized as the hardest?

Q5. Which of the following is NOT classified as a sedimentary rock?

Frequently asked questions

What are the three main types of rocks discussed in Chapter 5?

Chapter 5 discusses the three major classes of rocks: igneous rocks, sedimentary rocks, and metamorphic rocks.

What is the key characteristic of metamorphic rocks mentioned in the solutions?

A salient feature of metamorphic rocks highlighted is foliation, which refers to their layered or banded appearance.

How are igneous rocks formed?

Igneous rocks are formed through the cooling and solidification of molten rock material, either magma below the Earth's surface or lava on the surface.

What is the rock cycle?

The rock cycle describes the continuous process by which rocks are transformed from one type to another (igneous, sedimentary, metamorphic) under various geological conditions like temperature, pressure, and weathering.

Which mineral is known for its extreme hardness?

Diamond is identified as the hardest mineral among the options provided.

What is the difference between a single element mineral and other minerals?

A single element mineral, like gold or silver, is composed primarily of one element. Other minerals, such as mica, are compounds made up of multiple elements.

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