1. Ethane, with the molecular formula C2H6 has

(a) 6 covalent bonds.

(b) 7 covalent bonds.

(c) 8 covalent bonds.

(d) 9 covalent bonds

Ans:- Ethane, with the molecular formula C2H6 has 7 covalent bonds

2. Butanone is a four-carbon compound with the functional group
(a) carboxylic acid
(b) aldehyde
(c) ketone
(d) alcohol

Ans:- Answer is option C i.e Ketone.

3. While cooking, if the bottom of the vessel is getting blackened on the outside, it means that

(a) the food is not cooked completely.

(b) the fuel is not burning completely.

(c) the fuel is wet.

(d) the fuel is burning completely.

Ans:- Answer is option b. While cooking, if the bottom of the vessel is getting blackened on the outside indicates that the fuel is not burning completely.

4. Explain the nature of the covalent bond using the bond formation in CH3Cl.

Ans:- Carbon (C) has electronic configuration 2,4 and Chlorine (Cl) has electronic configuration 2,8,7.
Therefore, to completes, its octet configuration carbon requires 4 electrons and chlorine requires one electron. During the formation of covalent bonds, carbon shares its four electrons with three electrons from three H-atoms and one electron from chlorine atom forming four covalent bonds.


Thus CH3CI has three C-H bonds and one C-Cl bond.

5. Draw the electron dot structures for
(a)ethanoic acid.

Ans:-(a) Electron dot structures for ethanoic acid

ethanoic acid

(b) Electron dot structures for H2S


(c) Electron dot structures for propanone


(d) Electron dot structures for F2

6. What is a homologous series? Explain with an example.

Ans:- A homologous series is a series of compounds, which have the same functional group. This also contains a similar general formula and chemical properties. Since there is a change in the physical properties, we can say that there would be an increase in the molecular size and mass.

For example:- alcohol series is written as CH3OH, C2H5OH, C3H7OH, etc. The difference of each member is- CH2, group. The chemical properties of each member of the series are almost some but physical properties like melting point, boiling point, and solubility are different.

7. How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?

Does not react with sodium hydrogen carbonate
A good smell
No action in litmus paper
Burning taste

Ethanoic acid
Bubbles and fizzes with hydrogen carbonate
Smells like vinegar
Blue litmus paper to red
Sour taste

8. Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?

Ans.: A soap molecule has two ends- one is polar called hydrophilic which is attached to
the water molecule another part is non-polar called hydrophobic which is attached to oil droplet of the material. So when soap solution is added to the oily part of the material the polar part dissolved in water and non-polar part is dissolved in oil droplet forming a spherical shape containing water molecules, soap molecules and an oily part called a micelle.
No, micelle will not be formed in other solvents such as ethanol.

9. Why are carbon and its compounds used as fuels for most applications?

Ans:-Carbon and its compounds used as fuels for most applications because they have high calorific values and give out a lot of energy. Most of the carbon compounds give a lot of heat and light when burnt in air. 

10. Explain the formation of scum when hard water is treated with soap.

Ans:- Scrum is produced from the reaction of hard water with soap. We know that hard water contains Ca or Mg salt of sulphate or chloride. When treated with soap, it produces Ca or Mg salt of fatty acid present in the soap. As a result, precipitate will be formed which is called scum.

11. What change will you observe if you test soap with litmus paper (red and blue)?

Ans:- When we test soap with litmus paper color of red litmus paper it turns blue, but when we test soap with litmus paper color of blue litmus paper it remains the same.

12. What is hydrogenation? What is its industrial application?

Ans:- Hydrogenation is a process or a chemical reaction between hydrogen and other compounds. It is usually done in the presence of catalysts: for example nickel, palladium, or platinum.

Its industrial application is:-
Hydrogenation is used mainly to saturate organic compounds.

13. Which of the following hydrocarbons undergo addition reactions: C2H6, C3H8, C3H6, C2H2, and CH4.

Ans:- Unsaturated hydrocarbons undergo additional reactions. C3H6 and C2H2 are unsaturated hydrocarbons which undergo addition reactions.

14. Give a test that can be used to differentiate chemically between butter and
cooking oil.

Ans:- Butter is a saturated compound whereas cooking oil is an unsaturated compound. Therefore, when cooking oil is treated with a few drops of alkaline KMNO4, the pink colour of the solution disappears. Whereas butter can not change the colour of the solution.
15. Explain the mechanism of the cleaning action of soaps.

Ans:- The molecules of soap are sodium or potassium salts of long-chain carboxylic acids. The ionic-end of soap dissolves in water while the carbon chain dissolves in oil. The soap molecules, thus form structures called micelles where one end of the molecules is towards the oil droplet while the ionic-end faces outside. This forms an emulsion in water. The soap micelle thus helps in dissolving the dirt in water and we can wash our clothes clean.


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