Frank Solutions for Chapter 11A Organic Compounds Class 10 Chemistry ICSE
1. Which was the first organic compound synthesized in laboratory and by whom ?
Answer
Urea was the first organic compound synthesized in laboratory by Friedrish Wohler.
2. Write the molecular formulae of the third and fifth members of homologous series represented by general formula CnH2n-2.
Write the molecular formulae of the third and fifth members of homologous series represented by general formula CnH2n-2.
Write the molecular formulae of the third and fifth members of homologous series represented by general formula CnH2n-2.
Answer
As the general formula of the homologous series is CnH2n-2. so they represent alkynes.
Third member: C4H6
Fifth member: C6H10
Third member: C4H6
Fifth member: C6H10
3. Which of the following belong to same homologous series ?
C3H8 , C3H6 , C4H8 ,C4H6
C3H8 , C3H6 , C4H8 ,C4H6
Answer
C3H6 , C4H8 belong to same Homologous series.
4. How many isomers of the following hydrocarbons are possible ?
(a) C3H8
(a) C3H8
Answer
(a) C3H8 : Zero isomers. Alkanes with more than three carbon atoms form isomers.
(a) C3H8 : Two isomer
5. What is major source of organic compounds ?
Answer
Natural gas and Petroleum are one of the major sources of organic compound.
6. Give four differences between organic and inorganic compounds.
Answer
|
S. No. |
Organic Compounds |
Inorganic Compounds |
|
1. |
Occurs in living matter i.e. animals and plants |
Found from Non – living matter i.e. Minerals. |
|
2. |
They have low melting and boiling points. |
They have high melting and boiling points. |
|
3. |
Insoluble in water |
Soluble in water |
|
4. |
They are generally volatile and inflammable. |
They are generally non – volatile and non – combustible. |
7. Fill in the blanks :
(i) Organic compounds are essentially _____ compounds. They show _____ Reaction and their rates are ______.
(ii) One of the products of combustion of organic compounds is always ____ .
(iii) More than 90% of the known organic compounds are _____.
(iv) Vital force theory was discarded by the synthesis of _______ in laboratory.
(i) Organic compounds are essentially _____ compounds. They show _____ Reaction and their rates are ______.
(ii) One of the products of combustion of organic compounds is always ____ .
(iii) More than 90% of the known organic compounds are _____.
(iv) Vital force theory was discarded by the synthesis of _______ in laboratory.
Answer
(i) carbon , chemical
(ii) carbon dioxide
(iii) synthesised.
(iv) urea
8. Explain the fact that why organic compounds are large in number.
Answer
Organic compounds are large in number due to the following unique properties of Carbon atom :
(a) Tetra covalency of carbon: Carbon has four valence shell electrons. Thus it always forms covalent bonds by sharing electrons with other atoms.
(b) Catenation: It is the property of combining any number of carbon atoms to form straight chains, branched chains and rings of different sizes.
(c) Formation of multiple bonds: Due to small size carbon atom can form multiple bonds with not only carbon but with atoms of other elements like oxygen, nitrogen etc.
(d) Isomerism: It forms large number of compounds due to isomerism by means of which compounds having same molecular formula can have different structural formula.
(a) Tetra covalency of carbon: Carbon has four valence shell electrons. Thus it always forms covalent bonds by sharing electrons with other atoms.
(b) Catenation: It is the property of combining any number of carbon atoms to form straight chains, branched chains and rings of different sizes.
(c) Formation of multiple bonds: Due to small size carbon atom can form multiple bonds with not only carbon but with atoms of other elements like oxygen, nitrogen etc.
(d) Isomerism: It forms large number of compounds due to isomerism by means of which compounds having same molecular formula can have different structural formula.
9. (a) What is homologous series?
(b) What is the difference in molecular formula of any two adjacent homologues in terms of types of atoms and molecular mass?
(b) What is the difference in molecular formula of any two adjacent homologues in terms of types of atoms and molecular mass?
Answer
(a) A homologous series is a group of organic compounds having similar structures and similar chemical properties.
(b) The difference in molecular formula of any two adjacent homologues in terms of types of atoms is that that they differ by CH2 group i.e. by one carbon atom and two hydrogen atom.
(b) The difference in molecular formula of any two adjacent homologues in terms of types of atoms is that that they differ by CH2 group i.e. by one carbon atom and two hydrogen atom.
10. What is catenation? Why carbon show maximum tendency of catenation?
Answer
Carbon has the unique property of combining any number of carbon atoms to form straight chains, branched chains and rings of different sizes.
Carbon show maximum tendency of catenation due to :
Carbon show maximum tendency of catenation due to :
- Tetra covalency of carbon and
- Great strength of carbon - carbon bonds.
11. Give the name and formulae of one member of each of the following :
(a) Saturated Hydrocarbons
(b) Unsaturated Hydrocarbons
(a) Saturated Hydrocarbons
(b) Unsaturated Hydrocarbons
Answer
The name and Formulae of one member of each of following are :
(a) Saturated Hydrocarbons :
Formulae : CH4
Name : Methane
(b) Unsaturated Hydrocarbons :
Formulae : C2H4
Name : Ethene
12. (a) What is an alkyl group ?
(b) Give the names of any three alkyl groups. How are they formed ?
(b) Give the names of any three alkyl groups. How are they formed ?
Answer
(a) The group formed by the removal of one hydrogen atom from an alkane molecule is called an alkyl group.
(b) The three alkyl groups are :
(b) The three alkyl groups are :
13. Write the IUPAC name of the following :
Answer
(i) Pentane
(ii) 2, 2 - dimethylpropane
(iii) Pent - 2- ene
(iv) Propyne
(ii) 2, 2 - dimethylpropane
(iii) Pent - 2- ene
(iv) Propyne
14. Define a functional group with two examples. Write the functional groups for
(i) Alcohol
(ii) Ketone
(iii) Carboxylic acid
(i) Alcohol
(ii) Ketone
(iii) Carboxylic acid
Answer
A functional group may be defined as an atom or group of atoms present in a molecule which largely determines its chemical properties.
For Example : -OH: Alcohol, -CHO: Aldehyde
Functional group of :
(i) Alcohol : -OH
(ii) Ketone : >C-O
(iii) Carboxylic acid : -COOH
For Example : -OH: Alcohol, -CHO: Aldehyde
Functional group of :
(i) Alcohol : -OH
(ii) Ketone : >C-O
(iii) Carboxylic acid : -COOH
15. Define a functional group with two examples. Write the Functional groups for
(i) Alcohol
(ii) Ketone
(iii) Carboxylic acid
(i) Alcohol
(ii) Ketone
(iii) Carboxylic acid
Answer
A functional group may be defined as an atom or group of atoms present in a molecule which largely determines its chemical properties.
For Example : -OH: Alcohol, -CHO: Aldehyde
Functional group of :
(i) Alcohol : -OH
(ii) Ketone : > C-O
(iii) Carboxylic acid : -COOH
For Example : -OH: Alcohol, -CHO: Aldehyde
Functional group of :
(i) Alcohol : -OH
(ii) Ketone : > C-O
(iii) Carboxylic acid : -COOH
16. Give the names of the following functional groups :
Answer
17. Give the trivial names and IUPAC names of the following :
(a) C3H6
(b) C2H4
(c) C2H2
(d) CH3OH
(e) CH3COOH
Answer
|
S.No. |
Compound |
Trivial Name |
IUPAC |
|
(a) |
C3H6 |
Propylene |
Propene |
|
(b) |
C2H4 |
Ethylene |
Ethene |
|
(c) |
C2H2 |
Acetylene |
Ethyne |
|
(d) |
CH3OH |
Methylalcohol |
Methanol |
|
(e) |
CH3COOH |
Acetic acid |
Ethanoic acid |