Science – Carbon and its Compounds
Very Short Answer Type Questions
Q.1) Why is the conversion of ethanol to ethanoic acid an oxidation reaction?
Ans) CH₃CH₂OH → Alkaline KMnO₄ + Heat → CH₃COOH
Since, in this reaction, oxygen is added to ethanol, hence it is an oxidation reaction.
Q.2) What are oxidising agents?
Ans) Some substances like alkaline potassium permanganate and acidified potassium dichromate are capable of adding oxygen to others. These are known as oxidising agents.
Q.3) What would be the electron dot structure of carbon dioxide, which has the formula CO₂?
Ans) Electron dot structure of CO₂ is:
Q.4) What would be the electron dot structure of the molecule of sulphur which is made up eight atoms of sulphur?
Ans) Electron dot structure of a sulphur molecule :
Q.5) What will be the formula and electron dot structure of cyclopentane?
Ans) The formula for Cyclopentane is C5H10. Its electron dot structure is:
Q.6) What change will you observe if you test soap with litmus paper (red and blue)?
Ans) Since soap is basic in nature, it will turn red litmus blue. However, the colour of blue litmus will remain blue.
Q.7) Which of the following hydrocarbons undergo addition reactions?
C2H6 C3Hg, C3H6, C2H and CH4
Ans) Unsaturated hydrocarbons undergo addition reactions. Being unsaturated hydrocarbons, C₃H₆ and C₂H₂ will undergo addition reactions.
Q.8) How would you name the following compounds?
Ans) (i) Bromoethane, (ii) Methanol (formaldehyde), (iii) Hexyne.
Q.9) What is meant by functional group?
Ans) . An atom or a group of atoms which makes a carbon compound reactive and decides its properties is called a functional group.
Q.10) What are saturated hydrocarbons?
Ans) The hydrocarbons in which valency of carbon is satisfied by a single covalent bond are called saturated hydrocarbons. Alkanes like methane (CH₄), ethane (C₂H₆), etc. are examples of saturated hydrocarbons.
Q.11) What is a heteroatom? What is the heteroatom in alcohol functional group?
Ans) In a hydrocarbon chain, one or more hydrogen atoms can be replaced by other atoms according to their valencies. The element which replaces hydrogen in the chain is called a heteroatom. In alcohol (OH) functional group, oxygen is the heteroatom.
Q.12) Would you be able to check if water is hard by using a detergent?
Ans) Detergent gives lather with hard and soft water both, while a soap gives lather with soft water only. Thus, it is not possible to check if water is hard by using a detergent.
Q.13) Write only one example of each saturated and unsaturated carbon compound.
Ans) Saturated carbon compounds – Ethane (C₂H₆)
Unsaturated carbon compounds – Ethene (C₂H₄).
Q.14) Write only one example of each functional group aldehyde and carboxylic acid.
Ans) Functional group aldehyde – Ethanal (CH₃CHO)
Functional group carboxylic acid – Ethanoic acid (CH₃COOH).
Q.15) Draw the electron dot structure of ethane.
Ans) Electron dot structure of ethane C2H6.
Q.16) What is denatured alcohol? Write.
Ans) Ethyl alcohol is poisoned by adding methyl alcohol and copper sulphate in it to prevent drinking of it. This mixed alcohol is called denatured alcohol.
Q.17) How to use alcohol as a fuel? Write.
Ans) Alcohol is used as fuel in petrol as an additive since it is cleaner fuel which gives rise to only CO₂ and H₂O on burning enough oxygen.
Q.18) Write any two properties of Ethanol.
Ans) Two properties of Ethanol are: –
- It is a colourless, sweet smelling and pungent taste liquid.
- The boiling point is 78°C or 351K
Q.19) Write any two properties of Ethanoic acid.
Ans)
- It is a colorless, sour tasting liquid with a characteristic vinegar like odour.
- The boiling point is 118°C or 391K.