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Organic Chemistry: Some Basic Principles and Techniques — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryOrganic Chemistry: Some Basic Principles and Techniques5 Marks
Question
Why is a solution of potassium hydroxide used to absorb carbon dioxide evolved during the estimation of carbon present in an organic compound?
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Answer

Carbon dioxide is acidic in nature and potassium hydroxide is a strong base. Hence, carbon dioxide reacts with potassium hydroxide to form potassium carbonate and water as
$3 \mathrm{KOH}+\mathrm{CO}_2 \rightarrow \mathrm{~K}_2 \mathrm{CO}_3+\mathrm{H}_2 \mathrm{O}$
Thus, the mass of the U -tube containing KOH increases. This increase in the mass of U -tube gives the mass of $\mathrm{CO}_2$ produced. From its mass, the percentage of carbon in the organic compound can be estimated.

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