NIOS Class 10 Science Worksheet 28 Questions Answers – Carbon and its Compounds

This worksheet 28 contains questions based on Chapter 28 Carbon and its Compounds of NIOS Class 10 Science and Technology (212) along with complete and accurate answers.

This post explains the answers of questions given in the worksheet including explanation, diagrams. These solutions will help you complete your assignments and TMA also.

 

Carbon and its Compounds Worksheet 28 Solution

Q1. Name the element whose one of the allotropic forms is buckminsterfullerene.

Answer

Carbon is the element whose one of the allotropic forms is bickminsterfullerence.

Q2. In addition to some propane and ethane, LPG cylinders contain mainly two isomers of another alkane. Name the two isomers and write their condensed structural formulae.

Answer

In LPG cylinders along with small amounts of propane and ethane, the main component is butane which exists in two isomeric forms.

The two isomers of butane are:

i.       n- Butane (Normal butane)

ii.          isobutane (2-methylpropane)

Condensed Structural Formula of isomers of butane

(i)                   CH₃-CH₂-CH₂ -CH₃

(ii)               CH₃-CH -CH₃

          |

          CH₃

 

Q3. Name the black substance of pencil. Will the current flow through the electrical circuit when we use the sharpened ends of the pencil to complete the circuit?

Answer

The black substance used in pencil is Graphite which is an allotrope of carbon.

Yes, electric current will flow through the circuit when the sharpened ends of the pencil are used to complete the circuit because graphite is a good conductor of electricity.

 

Q4. How does graphite act as a lubricant?

Answer

Graphite acts as a lubricant because its structure is made of layers of carbon atoms arranged in hexagonal rings. The forces between these layers are very weak so the layers can slide easily over one another.

So, due to this sliding property, graphite reduces friction between surfaces and therefore it is used as a lubricant (dry lubricant).

Q5. Write the electron dot structure for : (i) ethane (ii) ethene (iii) ethyne.

Answer 

Q6. Give the IUPAC name of the following compounds:

C₂H₆

Answer

Ethane

Q7. Write the name of any two isomers represented by the molecular formula C₅H₁₂.

Answer

(i)         n-Pentane

(ii)     Iso pentane (2-methyl butane)

 

Q8. A neutral organic compound is warmed with some ethanoic acid and a little of conc. H₂SO₄. Vapors having sweet smell (fruity smell) are evolved. What type of functional group is present in this organic compound? The structural formula of an ester is:

Answer

When a neutral organic compound is warmed with ethanoic acid in the presence of concentrated H₂SO₄, and sweet-smelling vapour are produced, it indicates the formation of an ester. This reaction is called esterification.

The organic compound contains carbonyl group (C=O).

Structural formula of an ester

R-COO-R’

 

Q9. An organic acid ‘X’ is a liquid, which often freezes during winter time in cold countries, having the molecular formula C₂H₄O₂. On warming it with methanol in the presence of a few drops of concentrated sulphuric acid, a compound ‘Y’ with a sweet smell is formed.

(a)   Identify ‘X’ and ‘Y’. also write their formulae showing the functional group present in them.

(b)      Write the chemical equation for the reaction involved.

Answer

The organic acid X with molecular formula C₂H₄O₂ that freezes in cold weather is Ethanoic acid (Acetic acid). When ethanoic acid reacts with methanol in the presence of concentrated H₂SO₄, a sweet-smelling ester is formed.

(a)       X= Ethanoic acid

Formula = CH₃COOH

Y= Methyl ethanoate (ester)

Formula = CH₃COOCH₃

                                              H₂SO₄

(b)      CH3COOH + CH₃OH →CH₃COOCH₃ + H₂O

    This reaction is called Esterification.

 

Q10. Which of the following hydrocarbons can decolorise bromine water and which cannot? Why?

 C₆H₁₂, C₆H_14, C₆H₁₀

Answer

Unsaturated hydrocarbon (alkenes and alkynes) decolorise bromine water, while saturated hydrocarbons (alkanes) do not decolorise bromine water.

Explanation

    (i)     Unsaturated hydrocarbons contain double or triple bonds. These bonds react with bromine in an addition reaction, which causes the brown colour of bromine water to disappear.

   (ii)   Saturated hydrocarbons contain only single bonds and do not react with bromine water, so the colour remains unchanged.

     Related Topics 

   1. NIOS Class 10 Science Worksheets Solution Set 1 

   2. NIOS Class 10 Science Worksheets Solution Set 2