Class 10 Chemistry Chapter 1 Important Questions with Answers Kerala Syllabus

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SSLC Chemistry Chapter 1 Important Questions Kerala Syllabus

Nomenclature of Organic Compounds and Isomerism Class 10 Important Questions

Question 1.
What is the functional group of alcohols?
(-CO-, -CHO, -OH, -COOH)
Answer:
-OH

Question 2.
What is the structural formula for But-1-ene?
(CH₃ – CH₂ – CH₂ – CH₃, CH₃ – CH = CH – CH₃, CH₃ – CH₂ – CH = CH₂,
CH₃ – C ≡ C – CH₃)
Answer:
CH₃ – CH₂ – CH = CH₂,

Question 3.
The structural formula of a compound is given. Give the IUPAC name.

Answer:
2, 3, 5-Trimethylhexane

Question 4.
Some atoms or groups of atoms give organic compounds with certain chemical and physical properties.
a) What is such an atom or group of atoms called?
Answer:
Functional Groups

b) Give an example of such a group.
Answer:
Hydroxyl (-OH), Carboxylic acid (-COOH)

Question 5.
Write the molecular formula of Given compound?

Answer:
C₅H₁₂

Question 6.
Draw the structural formula of the functional isomer of CH₃ – CH₂ – CHO
Answer:
CH₃ – CO – CH₃

Question 7.
What is the representation of the ethyl radical?
Answer:
– CH₃ – CH₂

Question 8.
Illustrate the structure of the aromatic compound benzene, which has the molecular formula C₆H₆.
Answer:

Question 9.
Write the structural formula of given compounds
(i) 2, 3-Dimethylbutane
(ii) But-2-ene
Answer:
(i) 2, 3-Dimethylbutane

2, 3-Dimethyl butane

(ii) CH₃ – CH = CH – CH₃

Question 10.
(a) Write the molecular formula of the compound CH₃ – CH₂ – CH₂ – CH₂ -OH.
Answer:
C₄H₁₀O

(b) Write the structural formula of the position isomer of this compound.
Answer:

Question 11.
CH₃ – CH₂ – O – CH₃, CH₃ – CH₂ – CH₂ – OH
a) What similarities do these compounds have?
Answer:
Both compounds have the same molecular formula. (C₃H₈O)

b) What difference do these compounds show?
Answer:
The Functional groups of both compounds are different (-OH, -O-)

Question 12.
When naming an organic compound, the carbon atoms in the chain are numbered.

a) Is this correct? What is the reason?
Answer:
No,

b) If it is incorrect, number it correctly and write the IUPAC name of the compound.
Answer:
Numbering should be done in such a way that the carbon atom carrying the branch gets the lowest number.

Question 13.
Write the structural formula and IUPAC name of the following compounds C₂H₄ and C₂H₆

Answer:
C₂H₄ (Ethene)
C₂H₆ (Ethane)

Question 14.
a) CH₃ – CH₂ – CH₂ – CH₂ – CH₃ Write the IUPAC name of the compound
Answer:
Pentane

b) Write the structural formula of the chain isomer of this compound.
Answer:

Question 15.
Find the relationship between the pairs.
i) CH₃ – CH₂ – CHO: Propanal
CH₃ – CH₂ – COOH: –(a)—

ii) —(b)—: Ethanol
CH₃COCH₃: Propanone
Answer:
a) Propanoic acid
b) CH₃CH₂OH

Question 16.
Butan-1-ol and Methoxypropane are isomers. If so, what kind of isomers are they CH₃ – CH₂ – CH₂ – CH₂ – OH (Butan-1-ol), CH₃ – CH₂-CH₂ – O -CH₃ (Methoxypropane)
a) What type of isomers are they?
Answer:
Functional Group isomerism

b) Write the structural formulas of their other isomers.
Answer:
(i) Butan-2-ol

Ethoxyethane
(ii) CH₃CH₂OCH₂CH₃

Question 17.
Structural formulas of two organic compounds are given.
(i) CH₃ – O – CH₂ – CH₃
(ii) CH₃ – CH₂ – CH₂ – OH

a) Write the IUPAC name of each compound.
Answer:
i) Methoxyethane
ii) Propan-1-ol

b) Write one similarity between these compounds.
Answer:
The two compounds have the same molecular formula (C₃H₈O)

c) What is this phenomenon known as?
Answer:
Functional group isomerism

Question 18.
Write the possible isomer of this compound CH₃ – CH₂ – CH₂ – CH₂ -CH₃ – CH₂
Answer:
The possible isomers are

Question 19.
A saturated hydrocarbon has 5 carbon atoms in the main chain. A methyl radical is present on the second carbon atom.
a) Write the structural formula of the compound.
Answer:

b) What is the IUPAC name of the compound?
Answer:
2-Methylpentane

c) Write the structural formula of a chain isomer of this compound
Answer:
2, 2-Dimethylbutane

Question 20.
How many branches are there in the given compound?

Answer:
2

b) What are the names of the branches?
Answer:
Methyl, Methyl

c) What are the position numbers of the branches?
Answer:
2, 2

d) Write the IUPAC name of this compound.
Answer:
2, 2-Dimethylpropane

Question 21.
Look at the numbering of the carbon atoms in the compound given below.

a) Which of these is correct? Why
Answer:

In the nomenclature of hydrocarbons with double bonds, the numbering should be done in such a way that the carbon atoms linked by the double bond get the lowest position number.

b) Write the IUPAC name of this compound
Answer:
But-1-ene

Question 22.
Write the structural formula of the compounds given below
a) Propan-1-ol
b) Propanal
c) Propanone
Answer:
a) CH₃CH₂CH₂OH
b) CH₃ – CH₂ – CHO
c) CH₃ – CO – CH₃

Question 23.
Give the IUPAC Name of the compound

Answer:
2-Methylpropane

b) Write the Molecular formula of compound
Answer:
C₄H₁₀

c) Write the structure of the isomer of the compound
Answer:
CH₃ – CH₂ – CH₂ – CH₃ (Butane)

d) Name the type of isomerism exhibited by these compounds
Answer:
Chain isomerism

Question 24.
Which compounds have the molecular formula C₄H₁₀O?
Answer:
(i) CH₃CH₂CH₂CH₂OH
(ii) CH₃ – O – CH₂– CH₂ – CH₃
(iii) CH₃ – CH₂ – O – CH₂ – CH₃
(iv) Butan-2-ol

b) Find examples of position isomers and functional isomers from these.
Answer:
Position isomers: (i) and (iv), (ii) and (iii)
Functional isomers:(i) and (ii), (i) and (iii), (ii) and (iv), (iii) and (iv)

Question 25.
The Structural formula of two compounds is given below
(i) CH₃ – CH₂ – CH₂ – CHO
(ii) CH₃ – CH₂ – CO – CH₃
a) Write the IUPAC name of the compounds given
Answer:
(i) Butanal
(ii) Butan-2-one

b) Is it isomers? What is the reason
Answer:
These are isomers because they have the same molecular formula but different structural formula.

c) What type of isomers are these?
Answer:
Functional group isomerism

Question 26.
(a) Give the IUPAC name of the compounds given below.
(iii) CH₃CH₂CHO
(iv) CH₃CH₂CH₂OH
(v) CH₃OCH₂CH₃
(vi) CH₃COCH₃
Answer:
(i) Propanal
(ii) Propan-1-ol
(iii) Methoxyethane
(iv) Propan-2-one

(b) Which of these pairs are isomers? What type of isomers are these?
Answer: These are the pairs of isomers.
CH₃CH₂CH₂OH and CH₃ – O – CH₂ – CH₃
CH₃CH₂CHO and CH₃COCH₃
These compounds are functional group isomers.

Question 27.
Complete the table below

Functional Group	Compound containing the functional Group	IUPAC Name
——-(a)——-	CH3CH2OH	——–(b)
-COOH	——-(c)——-	Propanoic acid
——-(d)——-	——-(e)——-	Chloroethane
-OR	CH3OCH2CH3	——-(f)——-
——-(g)	CH3-CO-CH3	——-h——-

Answer:
(a) -OH
(b) Propan-1-ol
(c) CH₃ – CH₂ – COOH
(d) -Cl
(e) CH₃CH₂Cl
(f) Methoxyethane
(g) -CO-
(h) Propan-2-one

Question 28.
Certain details related to an organic hydrocarbon compound are given below:
• Molecular formula: C5HI2
• There is a methyl branch.
a) Draw the possible isomers for this compound and write their IUPAC names.
Answer:
(i) CH₃ CH₂ CH₂ CH₂ CH₃ (Pentane)

b) What type of isomerism do these exhibits?
Answer:
Chain isomerism

Question 29.
Write the IUPAC names for the following structural formulas:

Answer:
(i) 3-Ethylpentane
(ii) 3-Methylpentane

Question 30.
Write the position, name of the branch, and IUPAC name.

Answer:
The Position of the branch: 3
Name of the branch: Methyl
IUPAC Name:3-Methyl pentane

Question 31.
Write the IUPAC names for the following structural formula:

Answer:
2-Methylpentane

Question 32.
Some structural formulae are given below. Name them.

a) Number of carbon atoms in the main chain
Answer:
5

b) Number of branch/branches.
Answer:
2

c) Give the IUPAC name
Answer:
2, 4-Dimethyl pentane

Question 33.
Note the compound given below.

a) Number the longest chain of this compound from left to right and from right to left. In both cases, isn’t the position number of the first branch the same?
Answer:
Yes
b) Which is the second branch?
Answer:
Methyl group

c) When does this branch get the lowest number?
Answer:
While numbering from right to left

Question 34.
Give the IUPAC name of the given compounds

Answer:
(i) 2, 3, 3-Trimethyl pentane
(ii) 3, 3-Diethyl pentane

Question 35.
The structure of an alkyne is given.

(a) What is the molecular formula for this compound?
Answer:
C₄H₆

(b) Write the IUPAC name.
Answer:
But-1-yne

Question 36.
Write the structural formulae of the following compounds.
a. Pent-2-yne
b. But-1-ene
Answer:
a) CH₃ – C ≡ C – CH₂ – CH₃
b) CH₂ = CH – CH₂ – CH₃

Question 37.
Select the structural formula of the given compound from the box.
(i) Propene
(ii) But-2-yne

• CH2 = CH2, • CH3 – CH = CH2 • CH3 – CH2-C ≡ CH • CH3 – C ≡ C – CH3

Answer:
CH₃ – CH = CH₂: Propene
CH₃ – C ≡ C – CH₃: But-2-yne

Question 38.
What are functional groups in organic chemistry?
Answer:
Functional groups are specific atoms or groups of atoms within organic molecules that are responsible for the characteristic chemical properties of those molecules.

Question 39.
CH₃ – CH₂ – OH
CH₃ – O – CH₃
What are the functional groups in these compounds? Write their molecular formula.
Answer:
-OH &-O-CH₃
Molecular Formula: C₂H₆O

Question 40.
CH₃-COOH is the condensed formula of an organic compound.
a) To which category does the compound belong? (alcohol, ether, ester, carboxylic acid)
Answer:
Carboxylic acid
(b) Write the IUPAC name of this compound.
Answer:
Ethanoic acid

Question 41.
What is the key characteristic of aromatic hydrocarbons?
Answer:
The key characteristic of aromatic hydrocarbons is aromaticity. This property arises from a specific electron configuration within a closed ring of carbon atoms, often involving alternating single and double bonds.

Question 42.
What is an example of an aromatic hydrocarbon? What is its molecular formula?
Answer:
Benzene (C₆H₆) is the most famous example of an aromatic hydrocarbon. It has a hexagonal ring structure with delocalised electrons, contributing to its stability and unique chemical properties.

Question 43.
Why are aromatic hydrocarbons sometimes called aromatic?
Answer:
Aromatic hydrocarbons are often fragrant (hence the name “aromatic”). However, it’s important to note that not all aromatic compounds possess a pleasant odour.

Question 44.
What are isomers? How many types of isomerism are there?
Answer:
Isomers are compounds that share the same molecular formula but have different chemical and physical properties. There are four main types of isomerism : chain isomerism,functional isomerism .position isomerism and metamerism.

Question 45.
Can you identify the type of isomerism in the example of ethanol and methoxymethane?
Answer:
These are functional isomers. They have the same molecular formula (C2H60) but different functional groups (ethanol is an alcohol, while methoxymethane is an ether).

Question 46.
The structure of two organic compounds are given below:
(i) CH₃ – CH₂ – CH₂ – CH₂ – OH
(ii) CH₃ – CH₂ – O – CH₂ – CH₃

(a) Write the molecular formula of these compounds.
Answer:
C₄H₁₀O

(b) Which type of isomerism do they exhibit?
Answer:
Functional isomerism

(c) Write the structural formula of a position isomer of compound I
Answer:
Butan-2-ol