9- Carbon Compounds | Part 1 | Science I | Class 10

The blog presents the short Questions and Answers of the Chapter 9, Carbon Compounds, from Science Part I of Class 10 from Maharashtra State Board. These can be very useful for students preparing for SSC Board exams as well as competitive exams, as it includes the objective type basic concepts & fundamentals.

1. What are organic compounds ?

Ans. All the compounds having carbon as a constituent element are called as organic compounds.

2. Are all carbon compounds Organic Compounds ?

Ans. Most compounds having carbon are organic compounds, however the exceptions are carbon dioxide, carbon monoxide, carbide salts, carbonate salts and bicarbonate salts.

3. Why are intermolecular attractive forces weak in carbon compounds ?

Ans. Since the melting and boiling points of carbon compounds are found to be lower than 300◦C, the intermolecular forces of attraction are weak in carbon compounds.

4. What are the electrical properties of carbon compounds ?

Ans. Generally most of the carbon compounds are found to be bad conductor of electricity.

5. Do chemical bonding in carbon compounds produce ions ?

Ans. Chemical bonds in carbon compounds do not produce ions.

6. What is the driving force behind the formation of bond by an atom ?

Ans. The driving force behind the formation of bond by an atom is to attain the stable electronic configuration of the nearby noble gas and obtain stability.

7. What are the number of electrons in the valance shell of carbon ?

Ans. The valence K-shell of carbon contains 4 electrons.

8. Why does C atom become unstable inspite of its noble gas configuration of He ?

Ans. C atom becomes unstable inspite of its noble gas configuration of He, because losing all the four valence electrons the net positive charge increases and it develops a C4+ cation that has a small size and high net charge.

9. Why does C atom become unstable inspite of its noble gas configuration of Ne ?

Ans. (i) Carbon can attain the stable configuration of the noble gas neon (Ne) by accepting one by one as the four electrons in the valence shell.
(ii) In this method the net negative charge on the carbon atom goes on increasing while accepting every new electron. Therefore, more energy is required for accepting the next electron by overcoming the increasing repulsive force making the task more and more difficult.
(iii) Moreover the C4- anion ultimately formed would be unstable in spite of its noble gas configuration, as it would have a small size with high net charge making it difficult for the nuclear charge +6 to hold 10 electrons
around it.
Therefore, carbon atom does not take this route to attain a noble gas configuration.

10. How do atoms attain stability by sharing of valence shell ?

Ans. To attain the configuration of Neon by sharing four electrons involves following steps:                                                                        (i) Two atoms share valence electrons with each other.
(ii) Valence shells of both the atoms overlap and accommodate the shared electrons.        (iii) As a result, both the atoms attain a noble gas configuration without generating any net charge on them, which means that atoms remain electrically neutral.                            Due to these factors atoms attain stability. Therefore, carbon atom adopt this route to attain a noble gas configuration.

11. What is a covalent bond ?

Ans. The chemical bond formed by sharing of two valence electron between the two atoms is called covalent bond.

12. How are covalent bonds represented ?

Ans. (i) A covalent bond is represented clearly by drawing an electron dot structure.
(ii) In this method a circle is drawn around the atomic symbol and each of the valence electrons is indicated by a dot or a cross.
(iii) The covalent bond formed between the atoms is indicated by showing the circles around the atomic symbols crossing each other.
(iv) The shared electrons are shown in the overlapping regions of the two circles by dot or cross.

13. What is a line structure or structural formula ?

Ans. A covalent bond is also represented by a small line joining the symbols of the two atoms. The line structure is also called structural formula.

14. Explain covalent bonding in Hydrogen.

Ans. (i) The atomic number of hydrogen being 1, its atom contains 1 electron in K shell.
(ii) It requires one more electron to complete the K shell and attain the configuration of helium (He).
(iii) To meet this requirement two hydrogen atoms share their electrons with each other to form H2 molecule.                                           (iv) One covalent bond, that is a single bond is formed between two hydrogen atoms by sharing of two electrons.

15. How a Oxygen molecule is formed ?

Ans. The O2 molecule is formed by chemical combination of two oxygen atoms. Two oxygen atoms in O2 molecule are joined with each other by two covalent bonds, that is, a double bond.


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