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Some Basic Concepts of Chemistry question

2019 · 8 Apr · Shift 2 · Q19
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Some Basic Concepts of Chemistry question

2019 · 8 Apr · Shift 2 · Q19

JEE MainChemistrySome Basic Concepts of ChemistryMCQ+4 / −1
The percentage composition of carbon by mole in methane is :
  1. A
    80%
  2. B
    20%
  3. C
    75%
  4. D
    25%
View written solutionFree

Correct answer: B

  1. Write the formula of methane

    Methane is CH4\mathrm{CH_4}CH4​.

  2. Find total number of atoms in one molecule

    In CH4\mathrm{CH_4}CH4​:

    • Carbon atoms =1= 1=1
    • Hydrogen atoms =4= 4=4

    Total atoms =1+4=5= 1 + 4 = 5=1+4=5

  3. Find mole fraction / percentage by mole of carbon atoms

    Percentage composition of carbon by mole means the percentage of moles of carbon atoms among total moles of atoms.

    % carbon by mole=15×100=20%\%\text{ carbon by mole} = \frac{1}{5} \times 100 = 20\%% carbon by mole=51​×100=20%

  4. Match with the options

    • A: 80%80\%80%
    • B: 20%20\%20%
    • C: 75%75\%75%
    • D: 25%25\%25%

    Hence, the correct option is B.

  5. Verification with stored answer

    Stored correct answer: B

    Derived answer: B

    So, the derived answer agrees with the stored correct answer.

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