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Some Basic Concepts of Chemistry question

2025 · 8 Apr · Shift 2 · Q9
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Some Basic Concepts of Chemistry question

2025 · 8 Apr · Shift 2 · Q9

JEE MainChemistrySome Basic Concepts of ChemistryMCQ+4 / −1
On combustion 0.210 g of an organic compound containing C, H and O gave 0.127 g H2OH_2OH2​O and 0.307 g CO2CO_2CO2​. The percentages of hydrogen and oxygen in the given organic compound respectively are:
  1. A
    7.55, 43.85
  2. B
    6.72, 53.41
  3. C
    6.72, 39.87
  4. D
    53.41, 39.6
View written solutionFree

Correct answer: B

  1. Given data
  • Mass of organic compound =0.210 g= 0.210\,\text{g}=0.210g
  • Mass of H2OH_2OH2​O formed =0.127 g= 0.127\,\text{g}=0.127g
  • Mass of CO2CO_2CO2​ formed =0.307 g= 0.307\,\text{g}=0.307g

The compound contains only C,H,C, H,C,H, and OOO.

  1. Find mass of carbon from CO2CO_2CO2​

In 44 g44\,\text{g}44g of CO2CO_2CO2​, mass of carbon is 12 g12\,\text{g}12g.

So, carbon in 0.307 g0.307\,\text{g}0.307g of CO2CO_2CO2​ is

Mass of C=0.307×1244\text{Mass of C} = 0.307 \times \frac{12}{44}Mass of C=0.307×4412​ =0.08373 g= 0.08373\,\text{g}=0.08373g
  1. Find mass of hydrogen from H2OH_2OH2​O

In 18 g18\,\text{g}18g of H2OH_2OH2​O, mass of hydrogen is 2 g2\,\text{g}2g.

So, hydrogen in 0.127 g0.127\,\text{g}0.127g of H2OH_2OH2​O is

Mass of H=0.127×218\text{Mass of H} = 0.127 \times \frac{2}{18}Mass of H=0.127×182​ =0.01411 g= 0.01411\,\text{g}=0.01411g
  1. Find mass of oxygen in the compound

Since the compound contains only C,H,C, H,C,H, and OOO,

Mass of O=0.210−(0.08373+0.01411)\text{Mass of O} = 0.210 - (0.08373 + 0.01411)Mass of O=0.210−(0.08373+0.01411) =0.11216 g= 0.11216\,\text{g}=0.11216g
  1. Calculate percentage of hydrogen
%H=0.014110.210×100\%H = \frac{0.01411}{0.210} \times 100%H=0.2100.01411​×100 =6.72%= 6.72\%=6.72%
  1. Calculate percentage of oxygen
%O=0.112160.210×100\%O = \frac{0.11216}{0.210} \times 100%O=0.2100.11216​×100 =53.41%= 53.41\%=53.41%
  1. Match with options

The percentages of hydrogen and oxygen are:

6.72%,  53.41%6.72\%,\; 53.41\%6.72%,53.41%

This matches Option B.

  1. 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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