10th Class PS 4th Lesson Corbon and it's Compounds Questions and Answers (InTextbook)

10th Class PS 4th Lesson Corbon and it's Compounds Questions and Answers  (InTextbook)

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Question 1.
Ethane, with the molecular formula C2H6 has
a) 6 covalent bonds.
b) 7 covalent bonds. 
c) 8 covalent bonds.
d) 9 covalent bonds.
Answer:
b) 7 covalent bonds.

Question 2.
Butanone is a four-carbon compound with the functional group.
a) carboxylic acid.
b) aldehyde.
c) ketone.
d) alcohol.
Answer:
c) ketone.

Question 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.
c) the fuel is wet.
d) the fuel is burning completely.
Answer:
b) the fuel is not burning completely.

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

1. The covalent bond in CH3Cl is formed by sharing electrons between carbon and hydrogen or chlorine atoms.

2. In the formation of CH3Cl, one carbon atom shares one of its valence electrons with each of the three hydrogen atoms and one with the chlorine atom.

3. Simultaneously; the hydrogen atom shares its single valence electron with the carbon atom.

4.As a result, a total of 4 pairs of electrons (4 bonds) are shared between the carbon atom and the hydrogen and chlorine atoms, satisfying the octet/duet.

5. This sharing of electrons creates a covalent bond, specifically single covalent bonds, between carbon and hydrogen and carbon and chlorine.

6. The nature of the covalent bond in CH3Cl is characterized by the sharing of electrons between atoms to achieve a stable electron configuration, allowing all atoms to fill their outermost electron shells and become more stable and less reactive.

7. This sharing of electrons creates a strong connection between the atoms in the molecule, holding them together.

8. So, a covalent bond is a strong and stable bond.

Question 5.
Draw the electron dot structures for
a) ethanoic acid
b) H2S
c) propanone
d) F2.
Answer:
Electron dot structures :

Question 6.
What is a homologous series ? Explain with an example.
Answer:
Homologous series : A series in which every succeeding compound differs from the previous one by – CH2 group.

Example : The general formula for homologous series of alkanes is CnH2n + 2. CH4 (Methane), C2H6 (Ethane), C3H8 (Propane) and C4H10 (Butane)

Every homologous series have general formula. In alkane single bond is functional group, in alkane double bond and alkyne triple bond.

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

Ethanol	Ethanoic Acid
1) Ethanol has a pleasant smell	1) Ethanoic acid has the smell of Vinegar.
2) The boiling point of ethanol is 351 K.	2) The boiling point of ethanoic acid is 391 K.
3) Ethanol reacts with alkaline KMnO4 to give ethanoic acid.	3) Ethanoic acid does not react with alkaline KMnO4.
4) Ethanol does not react with sodium hydrogen carbonate.	4) It gives brisk effervescence with sodium hydrogen carbonateCH3COOH + NaHCO4 → CH3COONa + H2O + CO2↑

Question 8.
Why does micelle formation take place when soap is added to water? Will a micelle be formed in hither solvents such as ethanol also ?
Answer:
When soap is added to water, micelle formation takes place. This is because the hydrocarbon chains of soap molecule are hydrophobic which are insoluble in water, but the ionic ends of soap molecules are hydrophilic and hence soluble in water. Since soap is soluble in ethanol, so micelle for motion does not occur.

Question 9.
Why are carbon and its compounds used as fuels for most applications ?
Answer:
Carbon and its compounds are used as fuels because they burn in air releasing a large amount of heat energy
C + O2 → CO2 + Heat
CH4 + O2 → CO2 + H2O + Heat and tight.

Question 10.
Explain the formation of scum when hard water is treated with soap.
Answer:
Scum is formed when soap molecule reacts with calcium and magnesium ions present in hard water. The formation of scum slows down the cleaning action and also results in wastage of soap.

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

Soaps are alkaline, so it will turn red litmus blue and no effect on blue litmus paper.

Question 12.
What is hydrogenation? What is its industrial application ?
Answer:
Hydrogenation : Hydrogenation is a process in which a substance reacts with hydrogen in the presence of nickel or palladium as catalyst.

Industrial application : The process of hydrogenation is used to prepare vegetable ghee from vegetable oil.

Question 13.
Which of the following hydrocarbons undergo addition reactions: C2H6, C3H8, C3H6, C2H2 and CH4 ?
Answer:
C3H6 and C2H2 are unsaturated hydrocarbons, therefore, they will undergo addition reactions.
Question 14.
Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.
Answer:
Add bromine water to each of them. Cooking oil will decolourise bromine water showing that it is unsaturated, whereas butter will not decolourise bromine water showing that is saturated.
Question 15.
Explain the mechanism of the cleaning action of soaps.
Answer:
Cleaning action of Soaps:
The dirt present on clothes is organic in nature and insoluble in water.
Therefore, it cannot be removed by only washing with water.
When soap is dissolved in water, its hydrophobic ends attach themselves to the dirt and remove it from the cloth.
Then, the molecules of soap arrange themselves in micelle formation and trap the dirt at the centre of the cluster.
These micelles remain suspended in the water. Hence the dust particles are easily rinsed away by water.

Question 1.

What would be the electron dot the formula CO2?

Answer:

Question 2.
What would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur?
Answer:

Question 3.
How many structural isomers can you draw for pentane ?
Answer:
We can draw three structural isomers of pentane (C5H12)

Question 4.
What are the two properties of carbon, which lead to the huge number of carbon compounds we see around us ?

Answer:

Catenation and tetravalency.

Question 5.

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

Answer:

Question 6.

Draw the structures for the following compounds,
i) Ethanoic acid
ii) Bromopentane
iii) Butanone
iv) Hexanal.
Are structural isomers possible for bromopentane ?

Answer:

Yes, structural isomers are possible for bromopentane.

Question 7.

How would you name the following compounds ?
i) CH3 – CH2 – Br

Answer:

i) Bromoethane
ii) Methanal
iii) 1 – Hexyne

Question 8.

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

Answer:

Since the conversion of ethanol to ethanoic acid involves the addition of oxygen to ethanol, it is an oxidation reaction.

Question 9.

A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?

Answer:

Ethyne with oxygen gives enough heat can be used for welding whereas if it is burnt in air which contains nitrogen and other inactive gaseous contents, sufficient oxygen is not available for burning ethyne to give the required heat.

Question 10.

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

Answer:

Test	Alcohol	Carboxylic acid
1) Litmus test	No change in colour	Blue litmus solution turns red
2) Sodium carbonate	No action	Brisk effervescence is produced
3) Sodium metal test	H2 is given out with effervescence	H2 is produced but no effervescence

Question 11.

What are oxidising agents ?

Answer:

Those substances which give oxygen or replace hydrogen on reaction with other compounds are known as oxidising agents. For example, potassium permanganate (KMnO4.)

Question 12.

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

Answer:

No, because detergent is equally effective in hard water as well as soft water.

Question 13.

People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?

Answer:

Soap is able to remove dirt from clothes only in thin layers. Therefore, agitation or some similar activity is necessary so that totcil dirt is removed in layers of miscelles on continuous agitation and washing.

 

10th Class PS 4th Lesson Corbon and it's Compounds Questions and Answers (InTextbook)