Q1
1 markVery Short AnswerSection A

How many covalent bonds are there in a molecule of ethane, C2H6\text{C}_2\text{H}_6?

Carbon and its Compounds
Covalent Bonding in Carbon
Official Answer

There are 77 covalent bonds in a molecule of ethane (C2H6\text{C}_2\text{H}_6).

7 covalent bondssingle bondC-C bondC-H bondsethane

Marking Scheme

  • 1Stating the correct number of covalent bonds (7) (0.5 marks)
  • 2Showing the structural formula or explaining the breakdown (1 C-C bond and 6 C-H bonds) (0.5 marks)

Hint

Draw the structural skeleton of ethane by first linking the two carbon atoms and then distributing the six hydrogen atoms equally to satisfy the tetravalency of each carbon.

Quick Oral Answer

Ethane has 7 covalent bonds: 1 carbon-carbon single bond and 6 carbon-hydrogen single bonds.

Analysis & Explanation

Ethane is a saturated hydrocarbon (alkane). In saturated carbon compounds, all the valencies of carbon are satisfied by single covalent bonds shared between carbon-carbon and carbon-hydrogen atoms. Drawing the structural formula clearly shows the 7 shared pairs of electrons representing 7 single covalent bonds.

Common Mistakes

  1. 1Students often count only the 6 C-H bonds and forget to include the single C-C bond, incorrectly answering 6.
  2. 2Some students confuse the molecular formula and assume there are 8 bonds because of the subscripts.

Interesting Facts

Ethane is the second simplest alkane after methane and is a gaseous byproduct of petroleum refining and natural gas processing.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2011?

This question carries 1 mark in the CBSE Class 10 Science 2011 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Carbon and its Compounds" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Covalent Bonding in Carbon" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2011 paper?

This is a Very Short Answer question from Section A in the CBSE Class 10 Science 2011 paper.