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JEE Main levelSingle correct optionDifficulty 2 of 3si183

An organic compound contains only C, H, N and O. Analysis gave 61.0% C (Liebig), 5.1% H (Liebig) and 11.8% N (Dumas). The percentage of oxygen, obtained by difference, is

A $33.90%$
B $77.90%$
C $27.20%$
D $22.10%$

Answer: D

Oxygen is not estimated directly. %O =

100 - (61.0 + 5.1 + 11.8) = 22.1%

; all three measured percentages must be subtracted.

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