Isomers are the organic compounds having same molecular formula, but different arrangements of carbon atoms or simply different structures. For example, butane can exist in two isomeric forms such as n-butane and iso-butane.

Complete the following table: Straight chain of Carbon compounds Structural formula Molecular formula Name C CH 4 Methane C - C _____ _____ Ethane C - C - C _____ C 3 H 8 _____ C - C - C - C _____ _____

Straight chain of Carbon compounds Structural formula Molecular formula Name C CH 4 Methane C - C C 2 H 6 Ethane C - C - C C 3 H 8 Propane C - C - C - C C 4 H 10 Butane Methane, ethane, propane and butane are saturated hydrocarbons containing 1 , 2 , 3 and 4 carbon atoms respectively. Saturated hydrocarbons are the simplest of the hydrocarbon species and are composed entirely of single bonds. All these hydrocarbons belong to the alkane homologous series. The general formula for alkanes is C n H 2 n + 2 . So, the chemical formula for ethane is C 2 H 6 , for propane it is C 3 H 8 and the formula for butane is C 4 H 10 .

Match the pairs. Group A Group B a. C 2 H 6 1. Unsaturated hydrocarbon b. C 2 H 2 2. Molecular formula of an alcohol c. CH 4 O 3. Saturated hydrocarbon d. C 3 H 6 4. Triple bond

Saturated hydrocarbons are carbon compounds with only single bonds between the carbon atoms and the valencies are satisfied by hydrogen atoms. Alkanes are saturated hydrocarbons with the general formula C n H 2 n + 2 and the compound ethane with the formula C 2 H 6 is the second member of the alkane series. Unsaturated hydrocarbons are hydrocarbons with multiple bonds such as double or triple bonds between the adjacent carbon atoms. Alkynes with the formula C n H 2 n + 2 is an example of unsaturated hydrocarbons. Ethyne C 2 H 2 ⇔ HC ≡ CH with a triple bond is the first member of the alkyne series. A group of atoms present in a molecule which is responsible for the characteristic chemical properties of an organic compound is termed as a functional group. The functional group present in CH 4 O ⇔ CH 3 OH is alcohol, - OH group. Unsaturated hydrocarbons are hydrocarbons with multiple bonds such as double or triple bonds between the adjacent carbon atoms. Alkenes with the formula C n H 2 n is an example of unsaturated hydrocarbons. Propene with the formula C 3 H 6 ⇔ H 3 C - HC = CH 2 is the second member of the alkene series. Column A Column B a. C 2 H 6 3. Saturated hydrocarbon b. C 2 H 2 4. Triple bond c. CH 4 O 2. Molecular formula of an alcohol d. C 3 H 6 1. Unsaturated hydrocarbon

EASY

Earn 100

Draw the structure of propyne.

Important Questions on Carbon Compounds

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Write the names, molecular formula and structural formula of first four hydrocarbons.

EASY

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

What are isomers?

HARD

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Complete the following table:

Straight chain of Carbon compounds	Structural formula	Molecular formula	Name
$C$		${CH}_{4}$	Methane
$C - C$	_____	_____	Ethane
$C - C - C$	_____	$C_{3} H_{8}$	_____
$C - C - C - C$		_____	_____

EASY

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

The number of covalent bonds in Pentane

(C_{5} H_{12})

EASY

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

What is the value of

H - C - H

bond angle in methane?

EASY

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Draw the structure of the compound of carbon given below.

Chloropropane.

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Draw the structures of the following.

(i) Hexanal

(ii) Propanone

HARD

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Write the structural formulae and IUPAC names of the isomers represented by

C_{5} H_{12}

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

How many isomers of the following hydrocarbon are possible?

C_{4} H_{10}

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Draw a three-dimensional structure of methane molecule. Give the structural formula of the next two higher homologues of methane.

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

What is the shape of a methane molecule?

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Match the pairs.

Group A	Group B
a. $C_{2} H_{6}$	1. Unsaturated hydrocarbon
b. $C_{2} H_{2}$	2. Molecular formula of an alcohol
c. ${CH}_{4} O$	3. Saturated hydrocarbon
d. $C_{3} H_{6}$	4. Triple bond

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Give one example of a hydrocarbon, other than pentane, having more than three isomers.

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

How many structural isomers can you draw for pentane?

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Write the structural formula of butane.

MEDIUM

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

Write down the structures and names of two isomers of butane

(C_{4} H_{10})

EASY

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

In addition to some propane and ethane, LPG cylinders contain mainly two isomers of another alkane. Name the two isomers and write their condensed structural formula.

EASY

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

The hydrocarbon 2-methylbutane is an isomer of:

HARD

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

The number of covalent bonds in pentane (molecular formula

C_{5} H_{12}

) is:

HARD

Science>Chemistry>Carbon Compounds>Straight, Branched and Ring Chains of Carbon Atoms

How many isomers of the following hydrocarbons are possible?

C_{5} H_{12}

Draw the structure of propyne.

Important Questions on Carbon Compounds

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