Matric Notes Chemistry 10th Chapter 11 Organic Chemistry Exercise Short Questions

If you want to view other notes of Chemistry 10th Please Click Here.

Exercise Short Questions:

Q1. What is meant by term catenation? Give an example of a compound that displays catenation.

Ans. The ability of carbon atoms to link with other carbon atoms to form long chains and large rings is called catenation. e.g.

H₃C - CH₂ - CH₂ - CH₂ - CH₃               n-pentane

_{H3C - CH2 - CH2 - CH3        n-butane}

Q2. How is coal formed?

Ans. Coal was formed by the decomposition of dead plants buried under the Earth's crust millions of years ago.

Conversion of wood into coal is called carbonization. It is a very slow bio-chemical process. It takes place in the absence of air under high pressure and high temperature over a long period of time (about 500 millions of years)

Q3. What is the importance of natural gas?

Ans. The importance of natural gas is as:

1. Natural gas is used as fuel in homes as well as in industries.
2. It is used as fuel in automobiles as compressed natural gas (CNG).

Q4. Justify that organic compounds are used as food.

Ans. The food we eat daily such as milk, eggs, meat, vegetables, etc. contain carbohydrates, proteins, fats, vitamins etc. are all organic stuff.

Q5. How are alkyl radicals formed?

Ans. Alkyl radicals are derivatives of alkanes. They are formed by the removal of one of the hydrogen atom of an alkane and are represented by a letter 'R'. Their name is written by replacing 'ane' of alkane with 'yl'. Their general formula is C_nH_2n+1.

Example:

• Akyli radical                Name

1. CH₃-                            Methyl
2. C₂H₅-                           Ethyl

Q6. What is the difference between n-propyl and isopropyl? Explain with structure.

Ans. n-propyl

When terminal hydrogen is removed from propane, it is called n-propyl. i.e.

H₃C-CH₂-CH₃ ------> CH₃-CH₂-CH₂-

Propane                    n-propyl

Iso-propyl

When hydrogen is removed from central carbon of propane, it is called iso-propyl. i.e.

H₃C-CH₂-CH₂ ------> 
Propane                                Iso-propyl

Q7. Explain different radicals of butane.

Ans. Butane has two isomers n-butane and iso-butane. Following alkyl radicals are possible from them.

Q8. Define functional group with an example.

Ans. An atom or group of atoms or presence of double or triple bond which determines the characteristic properties of an organic compound is known as functional group.

Q9. What is an Ester group? Write down the formula of ethyl acetate.

Ans. Organic compounds in which carbon has  linkage is called Ester linkage. These compounds are called Esters.

Example:

Formula of ethyl acetate is 

Q10. Write down the dot and cross formula of propane and n-butane.

Ans.

Q11. Define structural formula. Draw the structural formulae of n-butane and iso-butane.

Ans. Structural formula of a compound represents the exact arrangement of the different atoms of various elements present in a molecule of a substance.

Following are structural formulae of butane (C₄H₁₀)

Q12. Write classification of coal.

Ans. Classification of coal

• Type of coal        Carbon content

1. Peat                       60%
2. Lignite                   70%
3. Bituminous            80%
4. Anthracite                90%

Q13. What are heterocyclic compounds? Give two examples.

Ans. Cyclic compounds that contain one or more atoms other than carbon atoms in their rings are called heterocyclic compounds.

For example:

Q14. Why are benzene and other homologous compounds of benzene called aromatic compounds?

Ans. Aromatic compounds:

The organic compounds which contain at least one benzene ring in their molecule are called aromatic compounds. A benzene ring is made up of six carbon atoms with three alternating double bonds. They are called aromatic because of aroma or smell they have.

They are also called benzenoid compounds.

For example: Benzene, Toluene and Naphthalene etc.