Class 10 Chemistry Chapter 4 - Carbon and Its Compounds Important Questions

 Class 10 - Carbon and Its Compounds 

Most Important Questions :- 

Q1. Why carbon cannot gain or lose four electrons ? 

Answer :- 

Carbon cannot gain four electrons because when it gain four electrons then 10 electrons over 6 protons will make the element unstable and therefore it cannot gain four electrons.

Carbon cannot lose four electrons because to lose four electrons large amount of energy is required which is not possible , therefore, losing four electrons is not possible for Carbon 

Q2. What are covalent compounds? Why are they different from ionic compounds? List their three characteristic properties. 

Answer:

Covalent compounds are those compounds which are formed by sharing of valence electrons between the atoms e.g., hydrogen molecule is formed by mutual sharing of electrons between two hydrogen atoms.

They are different from ionic compounds as ionic compounds are formed by the complete transfer of electrons from one atom to another e.g., NaCl is formed when one valence electron of sodium gets completely transferred to outer shell of chlorine atom. The characteristic properties of covalent compounds are:

(i) They are generally insoluble or less soluble in water but soluble in organic solvents.

(ii) They have low melting and boiling points.

(iii) They do not conduct electricity as they do not contain ions.

Q3. Write the molecular formula of first two members of homologous series having functional group -Cl. 

Answer:

The molecular formula of first two members of homologous series having -Cl functional group are CH3Cl and CH3CH2Cl.

Q4. What is homologous series of carbon compounds? 

Answer:

A homologous series is the family of organic compounds having the same functional group, similar chemical properties but the successive (adjacent) members of the series differ by a -CH2 unit or 14 mass units.

Q5. Define the term structural isomerism’. Explain why propane cannot exhibit this property. 

Answer:

Two or more organic compounds having the same molecular formula but different structures, are called structural isomers and the phenomenon is known as structural isomerism.

There is no possible isomers for propane as it contains three carbon atoms and it is not possible to have different arrangements of these carbon atoms.

Q6. What are oxidising agents?

Answer - Oxidising agents are those compounds that either replace hydrogen or add Oxygen to a compound. Ex: halogens, potassium nitrate, and nitric acid.

Q7. Why does micelle formation occur when soap is added to H2O? Do you observe if other solvents, like ethyl alcohol solvent, develop micelle formation?

Answer : 

Micelle formation occurs due to the dirt particles in normal and clean water. Two mediums are involved: one is pure water, and the other is dirt (also called impurities). The soap also has two forms:

(i) organic tail &

(ii) ionic head

So the organic tail mixes & dissolves with the dirt, whereas the oil, grease, and ionic head dissolve and mix with the water. Hence, when the material to be cleaned is separated from the water, the soap molecules take off the dirt in the water. Therefore, the soap cleans by forming closed structures through the mutual repulsion of the micelles (positively charged heads).

Several solvents, like ethanol, in which sodium or potassium salts of fatty acids do not mix, cannot form such micelles

Q8. What is Saponification reaction ?

Answer - 

Saponification is a chemical reaction where fats and oils are converted into soap and glycerol through a base-catalyzed hydrolysis process. 

Q9. Explain the formation of Micelle.

Answer :- 

Micelle formation occurs when amphipathic molecules, like soap, are dissolved in water. These molecules have both hydrophilic (water-loving) and hydrophobic (water-repelling) regions. When soap is added to water, the hydrophobic tails of the soap molecules aggregate together, minimizing contact with the water, while the hydrophilic heads remain in contact with the water. This self-assembly forms a spherical structure called a micelle, where the hydrophobic core is shielded from the water by the hydrophilic outer layer.

Q10. Differentiate between Soaps and Detergents.

Answer :- 

Soaps

•Soaps are potassium or sodium salts of a carboxylic acid having a long aliphatic chain attached to it.

• we can't use soaps in hard water .

• Soaps are Biodegradable.

Detergents

• Detergents are the potassium or sodium salts of a long alkyl chain ending with a sulfonate group.

• They are soluble in hard water.

• Detergents are non biodegradable.