Chapter 4 Carbon and its Compounds KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS

Chapter 4 Carbon and its Compounds KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS English medium Karnataka state board 2024,the Answers Are Prepared By Our Teachers Which Are Simple ,Pointwise,Easy To Read And Remember ,

Chapter 4 Carbon and its Compounds

1.What would be the electron dot structure of carbon dioxide which has the formula CO2 ?

Electron Dot Structure of Carbon Dioxide (CO2):

Carbon dioxide (CO2) molecule contains one carbon atom and two oxygen atoms.
Carbon has four valence electrons, while oxygen has six valence electrons each.
Carbon forms two covalent bonds with each oxygen atom by sharing its valence electrons.
The electron dot structure of carbon dioxide (CO2) would be represented as follows:

2.What would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur? (Hint – The eight atoms of sulphur are joined together in the form of a ring.)

Electron Dot Structure of a Molecule of Sulfur (S8):

A molecule of sulfur (S8) consists of eight atoms of sulfur joined together in the form of a ring.
Each sulfur atom contributes six valence electrons.
The sulfur atoms share electrons with neighboring atoms to complete their octet.
The electron dot structure of a molecule of sulfur (S8) would be represented as follows:

1.How many structural isomers can you draw for pentane?

Pentane (C5H12) can have three structural isomers.
The isomers are: n-pentane, isopentane, and neopentane.

2.What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?

Tetravalency: Carbon has a valency of four, allowing it to form four covalent bonds with other atoms.
Catenation: Carbon has the unique ability to form bonds with other atoms of carbon, leading to the formation of long chains, branched chains, or rings of carbon atoms.

3.What will be the formula and electron dot structure of cyclopentane?

Formula: C5H10
Electron dot structure: The structure would show five carbon atoms forming a ring with each carbon atom bonded to two hydrogen atoms.

4.Draw the structures for the following compounds.

(i) Ethanoic acid: CH3COOH

(ii) Bromopentane: C5H11Br

(iii) Butanone: CH3COCH2CH3

(iv) Hexanal: CH3(CH2)4CHO

5.How would you name the following compounds?

Ethanoic acid: Also known as acetic acid.
Bromopentane: Named as bromopentane.
Butanone: Also known as methyl ethyl ketone.
Hexanal: Named as hexanal.

2.Why is the conversion of ethanol to ethanoic acid an oxidation reaction?

- The conversion of ethanol to ethanoic acid involves the addition of oxygen atoms from oxidizing agents like alkaline potassium permanganate.
- This addition of oxygen increases the oxidation state of carbon in ethanol, turning it into ethanoic acid.
- Hence, this process is considered an oxidation reaction because oxygen is added to the starting material.

3.Why is a mixture of oxygen and ethyne used for welding instead of a mixture of ethyne and air?

Welding demands a high-temperature flame for effective metal melting and joining.
Oxygen and ethyne (oxyacetylene flame) create a much hotter flame compared to ethyne and air.
The higher flame temperature ensures efficient metal melting and welding.
Controlled reaction between ethyne and oxygen in pure oxygen produces the high-temperature flame necessary for welding.
Using ethyne and air may not provide sufficient heat due to lower oxygen concentration in air compared to pure oxygen.

1.Why is the conversion of ethanol to ethanoic acid an oxidation reaction?

The conversion of ethanol to ethanoic acid involves the addition of oxygen atoms from oxidizing agents like alkaline potassium permanganate.
This addition of oxygen increases the oxidation state of carbon in ethanol, turning it into ethanoic acid.
Hence, this process is considered an oxidation reaction because oxygen is added to the starting material.

2.Why a mixture of oxygen and ethyne is burnt for welding and not a mixture of ethyne and air?

Welding requires a high-temperature flame, achievable with a mixture of oxygen and ethyne (oxyacetylene flame).
This mixture provides a higher flame temperature than a mixture of ethyne and air, ensuring efficient metal melting and welding.
Ethyne reacts with oxygen in a controlled manner, producing a high-temperature flame suitable for welding, unlike a mixture with air, which has a lower oxygen concentration.

1.How would you distinguish experimentally between an alcohol and a carboxylic acid?

Therefore, Carboxylic acid and Alcohol can be distinguished by using Sodium bicarbonate as, Carboxylic acid produces a brisk effervesce when reacted with it, whereas Alcohols do not produce anything when reacted with Sodium bicarbonate.

2.What are oxidising agents?

An oxidizing agent is a substance that oxidizes other substances involved in the reaction by gaining or accepting electrons from them

1.Would you be able to check if water is hard by using a detergent?

No, detergents don’t react with hardness ions like calcium and magnesium.
Hence, they don’t indicate water hardness directly.
Specific tests, such as soap foam or titration with EDTA solution, are needed to assess water hardness accurately.

2.Why is agitation necessary for clean clothes?

Agitation dislodges dirt by breaking bonds.
It spreads soap evenly for better cleaning.
Agitation enhances interaction between soap and dirt.
It’s achieved through machine movement or manual beating.
Without agitation, dirt removal is incomplete.

EXERCISES

1.Ethane, with the molecular formula C2H6 has

(a) 6 covalent bonds.

(b) 7 covalent bonds.

(d) 9 covalent bonds.

ANSWER:-

Ethane, with the molecular formula C2H6 has:

2.Butanone is a four-carbon compound with the functional group

(a) carboxylic acid.

(b) aldehyde.

(d) alcohol.

ANSWER:-

Butanone is a four-carbon compound with the functional group:

3.While cooking, if the bottom of the vessel is getting blackened on the outside, it means that

(a) the food is not cooked completely.

(b) the fuel is not burning completely.

(d) the fuel is burning completely.

ANSWER:-

While cooking, if the bottom of the vessel is getting blackened on the outside, it means that:

(b) the fuel is not burning completely.

4.Explain the nature of the covalent bond using the bond formation in CH3Cl.

Explanation of the nature of the covalent bond using the bond formation in CH3Cl:

Covalent bonds involve the sharing of electrons between atoms.
In CH3Cl, carbon shares one electron with three hydrogen atoms and one electron with a chlorine atom.
Each bond formed represents a shared pair of electrons between the atoms, creating a stable molecule

5.Draw the electron dot structures for

(a) ethanoic acid.

(b) H2 S.

(d) F2 .

Electron dot structures

6.What is an homologous series? Explain with an example.

An homologous series is a series of organic compounds in which each member differs from the previous one by a common structural unit, usually a -CH2- group.
All members of an homologous series have similar chemical properties due to the presence of the same functional group.
Example: The homologous series of alkanes, where each member differs by a CH2 unit. For instance, methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10) are all part of the alkane homologous series.

7.How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?

Physical properties differentiation:

Ethanol is a colorless liquid at room temperature, while ethanoic acid is a colorless liquid with a pungent odor resembling vinegar.
Ethanol has a boiling point of 78.37°C, while ethanoic acid has a higher boiling point of 118.1°C due to hydrogen bonding.

Chemical properties differentiation:

Ethanol reacts with sodium to produce hydrogen gas and sodium ethoxide, while ethanoic acid reacts with sodium carbonate to produce carbon dioxide gas, water, and sodium acetate.
Ethanol undergoes dehydration to form ethene in the presence of concentrated sulphuric acid, while ethanoic acid does not undergo dehydration.

8..Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?

Micelle formation occurs because soap molecules have both hydrophobic (water-repelling) and hydrophilic (water-attracting) parts.
When soap is added to water, the hydrophilic part interacts with water molecules while the hydrophobic part interacts with oil or grease.
This arrangement forms micelles, where the hydrophobic tails cluster together in the center, shielding them from water, while the hydrophilic heads remain in contact with the water.
Micelle formation is specific to water because it involves the interaction between polar water molecules and the charged parts of the soap molecules. In other solvents like ethanol, micelle formation may not occur due to different solvent-solute interactions.

9.Why are carbon and its compounds used as fuels for most applications?

Carbon compounds, especially hydrocarbons, contain high energy bonds that release a large amount of heat and light upon combustion.
Carbon compounds are abundant, readily available, and can be easily obtained from natural sources like fossil fuels (coal, petroleum).
They can be efficiently transported and stored, making them convenient for various applications.
Carbon compounds burn cleanly in sufficient oxygen, producing mainly carbon dioxide and water vapor, which are less harmful to the environment compared to other fuels like coal.
Their combustion reactions are well understood and controllable, making them suitable for a wide range of applications, including heating, cooking, and transportation.

10.Explain the formation of scum when hard water is treated with soap.

Formation of scum when hard water is treated with soap:

Hard water contains dissolved calcium and magnesium ions.
When soap is added to hard water, it reacts with the calcium and magnesium ions to form insoluble calcium and magnesium salts of fatty acids.
These insoluble salts precipitate out of solution and form a curdy, scummy layer on the surface of the water.
This scum is difficult to rinse away and reduces the effectiveness of the soap in cleaning.

11.What change will you observe if you test soap with litmus paper (red and blue)?

Change observed when testing soap with litmus paper:

Red litmus paper remains unchanged when in contact with soap, indicating that soap is neutral or slightly alkaline.
Blue litmus paper turns pink or red when in contact with soap, indicating that soap is slightly alkaline.

12.What is hydrogenation? What is its industrial application?

Hydrogenation and its industrial application:

Hydrogenation is the chemical process of adding hydrogen molecules to unsaturated hydrocarbons.
It is commonly used in the food industry to convert unsaturated vegetable oils into saturated fats, making them solid at room temperature.
This process is used to produce margarine and shortening, which have desirable properties for baking and cooking.

13.Which of the following hydrocarbons undergo addition reactions: C2H6 , C3H8 , C3H6 , C2H2 and CH4 .

Hydrocarbons undergoing addition reactions:

C3H6 (Propene) and C2H2 (Ethyne) undergo addition reactions due to the presence of double or triple bonds.
C2H6 (Ethane), C3H8 (Propane), and CH4 (Methane) do not undergo addition reactions as they only contain single bonds between carbon atoms.

14.Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.

Test to differentiate between saturated and unsaturated hydrocarbons:

Add bromine water to the hydrocarbon sample.
Saturated hydrocarbons (alkanes) do not react with bromine water and the solution remains orange.
Unsaturated hydrocarbons (alkenes and alkynes) react with bromine water, causing the solution to decolorize due to the addition of bromine across the double or triple bond.

15.Explain the mechanism of the cleaning action of soaps

Mechanism of the cleaning action of soaps:

Soaps are amphiphilic molecules with a hydrophobic tail and a hydrophilic head.
In water, soap molecules form micelles with the hydrophobic tails directed inward and hydrophilic heads outward.
The hydrophobic tails interact with oily dirt, while the hydrophilic heads interact with water.
As a result, the oily dirt is emulsified and trapped within the micelles, allowing it to be rinsed away with water.

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