Class 10 Chemistry Chapter 11
Organic Compounds
Important Questions

Here, you'll discover significant inquiries pertaining to Chapter 11: Organic Compounds for ICSE Class 10 Chemistry. These inquiries are carefully designed to aid students in preparing for the ICSE Class 10 Chemistry Examination in 2023–24. Engaging with different question formats allows students to address uncertainties, improve their exam preparedness, boost their self-assurance, and polish their ability to solve problems.

Introduction

In ICSE Class 10 "Organic Compounds," you will explore a range of fundamental concepts related to carbon-based compounds. The chapter covers various aspects, including the distinctive characteristics of carbon atoms, such as their tetra-valency and catenation properties. It also delves into the formation of single, double, and triple bonds in organic compounds, the structure of compounds featuring these bonds, and the presentation of structural formulae for hydrocarbons. The chapter introduces you to isomerism, particularly structural isomerism involving chain and position isomerism. It further explores the properties and gradation in properties of alkane, alkene, and alkyne series, highlighting their relationships with molecular mass and molecular formula. Additionally, you will learn about the nomenclature of hydrocarbons with simple functional groups, considering rules like the longest chain rule and the smallest number for functional groups rule. This includes both trivial and IUPAC names for compounds featuring a single functional group. Specifically, the chapter covers:

• Alkanes: This section provides a general formula for alkanes and discusses the preparation methods for methane and ethane from various sources. It explores the complete combustion of methane and ethane and their reactions with chlorine through substitution.
• Alkenes: Alkenes, which are unsaturated hydrocarbons with a double bond, are exemplified by ethene. You'll learn about the preparation of ethene through dehydrohalogenation reactions and dehydration reactions.
• Alkynes: Alkynes, characterised by triple bonds, are exemplified by ethyne. The chapter covers methods of preparation using calcium carbide and 1,2-dibromoethane (ethylene dibromide).
• Uses of Methane, Ethane, Ethene, and Ethyne: This section explores the practical applications of these hydrocarbons.
• Preparation of Ethanol: You will learn how to prepare ethanol by hydrolyzing alkyl halides.
• Properties of Ethanol: The chapter examines both physical properties, such as nature, solubility, density, and boiling points, and chemical properties, including combustion, reactions with sodium, ester formation with acetic acid, and dehydration using concentrated sulfuric acid to produce ethene.
• Denatured and Spurious Alcohol: The concept of denatured and spurious alcohol is discussed.
• Important Uses of Ethanol: The practical applications of ethanol are highlighted.
• Structure and Properties of Acetic Acid: The chapter covers the structure of acetic acid and explores its physical properties, such as odour and the formation of glacial acetic acid. Chemical properties, including reactions with litmus, alkalis, and alcohol.

What are Organic Compounds ?

In ICSE Class 10 "Organic Compounds," the term "organic compounds" refers to a broad and diverse category of chemical compounds primarily composed of carbon atoms. These compounds form the foundation of organic chemistry, and they play a crucial role in the study of carbon-based chemistry. Organic compounds are characterised by the presence of carbon atoms, often bonded to hydrogen, oxygen, nitrogen, sulphur, and other elements. What makes carbon unique in organic compounds is its ability to form stable covalent bonds with a variety of other elements and itself. This property, known as catenation, enables carbon to create complex and diverse molecular structures. In this chapter, you will explore various fundamental aspects of organic compounds, including the unique nature of carbon atoms, their tetra-valency, and their propensity for forming single, double, and triple bonds. You will also delve into the structure and nomenclature of hydrocarbons, which are compounds consisting solely of carbon and hydrogen. Furthermore, the chapter covers isomerism, which arises from the different arrangements of atoms within organic molecules, resulting in compounds with the same molecular formula but distinct structural arrangements and properties. Additionally, you will explore the properties and reactions of different series of organic compounds, including alkanes (saturated hydrocarbons), alkenes (unsaturated hydrocarbons with double bonds), and alkynes (unsaturated hydrocarbons with triple bonds). The chapter provides insights into their gradation in properties and their relationships with molecular mass and molecular formula. Through the study of organic compounds, you will gain a comprehensive understanding of the fundamental principles that govern the behaviour and structure of carbon-based molecules. This knowledge forms the basis for further exploration into the diverse world of organic chemistry, including the study of functional groups, reactions, and the vast array of organic compounds found in nature and synthesised for various applications.

Class 10 Chemistry Chapter 11 Organic Compounds Important Questions and Answers

Q1. The unsaturated hydrocarbons undergo :

Options

(a) A substitution reaction
(b) An oxidation reaction
(c) An addition reaction
(d) None of these

Ans. (c) An addition reaction

Explanation:
Unsaturated hydrocarbons are those hydrocarbons in which there is at least one double or triple bond. For example, Ethene (CH₂=CH₂) is an unsaturated hydrocarbon and they undergo additional reaction only.

Q2. Carbon atom form a large number of compounds with other elements because of its:

Options

(a) Catenation
(b) Allotropy
(c) Electronegativity
(d) None of these

Ans. (a)
Explanation:
Carbon atoms are small in size and this enables its nucleus to hold on the shared pair of electrons quite strongly.

Q3. What is the special feature of the structure of:
(a) C₂H_4
‍(b) C₂H₂

Explanation:
(a) C₂H₄ contains a double bond between two carbon atoms.
(b) C₂H₂ contains a triple bond between two carbon atoms.

Q4. The molecules of the alkene family are represented by a general formula C_nH_2n. Now answer the following :
(i) What do n and 2n signify?
(ii) What is the lowest value which can be assigned to n?
(iii) What is the molecular formula of alkene, when n = 4?
(iv) What is the structural formula of the first member of the alkene family?

Explanation:
(i) n = Number of C-atoms in a molecule of alkene.
2n = Number of H-atoms in a molecule of alkene.
(ii) The lowest value of n is 2.
(iii) Butene (C₄H₈).
The first member of the alkene family is C₂H₄.
(iv) It is called ethene, the structural formula is :

Q5. Which was the first organic compound synthesised in the laboratory and by whom?

Explanation:
Urea was the first organic compound synthesised in a laboratory. It was done by Friedrish Wohler in 1828 by heating ammonium cyanate (an inorganic compound).
Ammonium cyanate is an inorganic compound while urea is an organic compound. Wohler prepared urea without involving living organisms. At the point of starting modern organic chemistry he has been dubbed as the father of organic chemistry. Let's have a look at some important uses of urea and its properties. Human urine has a major organic component as urea. Urea is used as a fertiliser due to its high levels of nitrogen. Dry, rough skin conditions can be treated by urea. It is also helpful in removing dead tissues. Urea dissolves in the kidney and blood excretes it in urine. It is non-toxic, colourless and can be dissolved in water. In urea there is a carbonyl group attached to two amide groups. In a carbonyl group, a double bonded carbon atom bonded to an oxygen atom. It is also called carbide and can be readily prepared from carbon dioxide and ammonia. Urea behaves as a weak mono acidic base.

ICSE Class 10 Chemistry Chapter wise Important Questions

Conclusion

The exploration of "Organic Compounds" in ICSE Class 10 Chemistry Chapter 11 has provided a foundational understanding of this fascinating branch of chemistry. This chapter delves into the intricate world of carbon-based compounds, offering a glimpse into the unique properties and characteristics that make organic chemistry both captivating and essential.The study of hydrocarbons, encompassing alkanes, alkenes, and alkynes, has allowed us to grasp the diversity and gradation in properties within this class of compounds. For those seeking to excel in the realm of organic chemistry, additional practice and resources are invaluable. To enhance your proficiency and reinforce your comprehension of organic compounds, oswal.io offers a comprehensive collection of questions and study materials. These resources not only provide opportunities to assess your knowledge but also serve as valuable tools to aid your learning journey.

Frequently Asked Questions

Q1 : What is meant by organic compounds?

Ans: Organic compound is of a large class of chemical compounds in which one or more carbon atoms are covalently paired with other elements atoms, most commonly hydrogen, oxygen, or nitrogen.

Q2 : What is an example of an organic chemical?

Ans:  Types include gasoline, plastics, detergents, colourants, food additives, natural gas, and drugs. Soap and detergent are two different examples of organic chemistry, although both are used for washing.

Q3 : What are the uses of organic compounds?

Ans: Organic molecules are used in a variety of industries in human society, including food, pharmaceuticals, fuels, and building, to name but a few. Alkanes include chemical substances such as propane, octane, and methane. These are commonly used as oils for items like gasoline in the car and heating/cooking oil in the home.

Q4 : Why are organic compounds useful?

Ans:  Organic compounds are essential because they contain carbon in all living organisms. They are the basic components that move the world in many of the cycles. For example, the carbon cycle which involves exchanging carbon in photosynthesis and cell respiration between plants and animals.

Q5 : What organic compounds are used in medicine?

Ans: Compounds used as medicinal products are most usually organic compounds, sometimes divided into large groups of small organic molecules (e.g., atorvastatin, fluticasone, clopidogrel) and “biologics” (infliximab, erythropoietin, insulin glargine), the latter more widely used as protein medicinal products.