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Alcohols Phenols and Ethers question

2020 · 6 Sep · Shift 2 · Q10
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Alcohols Phenols and Ethers question

2020 · 6 Sep · Shift 2 · Q10

JEE MainChemistryAlcohols Phenols and EthersNumerical+4 / −1
A solution of phenol in chloroform when treated with aqueous NaOH gives compound P as a major product. The mass percentage of carbon in P is ‾\underline{\hspace{2cm}}​. (to the nearest integer) (Atomic mass : C = 12; H = 1; O = 16)
Numerical answer
View written solutionFree

Correct answer: 69

  1. Identify the reaction

Phenol dissolved in chloroform and treated with aqueous NaOH undergoes the Reimer–Tiemann reaction.

The major product is o-hydroxybenzaldehyde (salicylaldehyde).

So, compound PPP is:

o-hydroxybenzaldehyde=C7H6O2\text{o-hydroxybenzaldehyde} = C_7H_6O_2o-hydroxybenzaldehyde=C7​H6​O2​

(Structure: benzene ring with one −OH-OH−OH and one −CHO-CHO−CHO group)

  1. Calculate molar mass of PPP

For C7H6O2C_7H_6O_2C7​H6​O2​:

Molar mass=7(12)+6(1)+2(16)\text{Molar mass} = 7(12) + 6(1) + 2(16)Molar mass=7(12)+6(1)+2(16) =84+6+32=122= 84 + 6 + 32 = 122=84+6+32=122
  1. Calculate mass of carbon in one mole of PPP

There are 777 carbon atoms.

Mass of carbon=7×12=84\text{Mass of carbon} = 7 \times 12 = 84Mass of carbon=7×12=84
  1. Find mass percentage of carbon
%C=84122×100\%C = \frac{84}{122} \times 100%C=12284​×100 =68.85%= 68.85\%=68.85%

To the nearest integer:

69\boxed{69}69​
  1. Comparison with stored answer

Stored correct answer = 696969

Our derived answer = 696969

So, the answer agrees with the stored answer.

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