Hydrocarbons · JEE Advanced previous year questions

2023 2 questions

1. Q502023 · 4 Jun 2023 · Paper 2· Numerical answer

   PARAGRAPH II A trinitro compound, 1,3,5-tris-(4-nitrophenyl)benzene, on complete reaction with an excess of $Sn/HCl$ gives a major product, which on treatment with an excess of $\mathrm{NaN}{\mathrm{O}}_2/HCl$ at $0{}^{\circ }\mathrm{C}$ provides $\mathbf{P}$ as the product. $\mathbf{P}$, upon treatment with excess of ${\mathrm{H}}_2\mathrm{O}$ at room temperature, gives the product $\mathbf{Q}$. Bromination of $\mathbf{Q}$ in aqueous medium furnishes the product $\mathbf{R}$. The compound $\mathbf{P}$ upon treatment with an excess of phenol under basic conditions gives the product $\mathbf{S}$. The molar mass difference between compounds $\mathbf{Q}$ and $\mathbf{R}$ is $474{\text{ g mol}}^{-1}$ and between compounds $\mathbf{P}$ and $\mathbf{S}$ is $172.5{\text{ g mol}}^{-1}$. Q.16 The number of heteroatoms present in one molecule of $\mathbf{R}$ is _____. [Use: Molar mass (in ${\text{g mol}}^{-1}$): $\mathrm{H}=1,\mathrm{C}=12,\mathrm{N}=14,\mathrm{O}=16,\mathrm{Br}=80,\mathrm{Cl}=35.5$ Atoms other than $\mathrm{C}$ and $\mathrm{H}$ are considered as heteroatoms]

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   Answer: 9 to 9

2. Q512023 · 4 Jun 2023 · Paper 2· Numerical answer

   PARAGRAPH II A trinitro compound, 1,3,5-tris-(4-nitrophenyl)benzene, on complete reaction with an excess of $Sn/HCl$ gives a major product, which on treatment with an excess of $\mathrm{NaN}{\mathrm{O}}_2/HCl$ at $0{}^{\circ }\mathrm{C}$ provides $\mathbf{P}$ as the product. $\mathbf{P}$, upon treatment with excess of ${\mathrm{H}}_2\mathrm{O}$ at room temperature, gives the product $\mathbf{Q}$. Bromination of $\mathbf{Q}$ in aqueous medium furnishes the product $\mathbf{R}$. The compound $\mathbf{P}$ upon treatment with an excess of phenol under basic conditions gives the product $\mathbf{S}$. The molar mass difference between compounds $\mathbf{Q}$ and $\mathbf{R}$ is $474{\text{ g mol}}^{-1}$ and between compounds $\mathbf{P}$ and $\mathbf{S}$ is $172.5{\text{ g mol}}^{-1}$. Q.17 The total number of carbon atoms and heteroatoms present in one molecule of $\mathbf{S}$ is _____. [Use: Molar mass (in ${\text{g mol}}^{-1}$): $\mathrm{H}=1,\mathrm{C}=12,\mathrm{N}=14,\mathrm{O}=16,\mathrm{Br}=80,\mathrm{Cl}=35.5$ Atoms other than $\mathrm{C}$ and $\mathrm{H}$ are considered as heteroatoms]

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   Answer: 51 to 51