Mole Concept & Stoichiometry · JEE Advanced previous year questions

2024 6 questions

1. Q422024 · 26 May 2024 · Paper 2· Numerical answer

   To form a complete monolayer of acetic acid on 1g of charcoal, 100 mL of 0.5 M acetic acid was used. Some of the acetic acid remained unadsorbed. To neutralize the unadsorbed acetic acid, 40 mL of 1 M NaOH solution was required. If each molecule of acetic acid occupies $\mathbf{P}\times 10^{-23}{\mathrm{m}}^2$ surface area on charcoal, the value of $\mathbf{P}$ is ____. [Use given data: Surface area of charcoal $=1.5\times 10^2{\mathrm{m}}^2{\mathrm{g}}^{-1}$; Avogadro’s number $({\mathrm{N}}_{\mathrm{A}})=6.0\times 10^{23}\mathrm{mo}{\mathrm{l}}^{-1}$]

   Show answer

   Answer: 2500

2. Q472024 · 26 May 2024 · Paper 2· Numerical answer

   An organic compound $\mathbf{P}$ having molecular formula ${\mathrm{C}}_6{\mathrm{H}}_6{\mathrm{O}}_3$ gives ferric chloride test and does not have intramolecular hydrogen bond. The compound $\mathbf{P}$ reacts with 3 equivalents of $\mathrm{N}{\mathrm{H}}_2\mathrm{OH}$ to produce oxime $\mathbf{Q}$. Treatment of $\mathbf{P}$ with excess methyl iodide in the presence of KOH produces compound $\mathbf{R}$ as the major product. Reaction of $\mathbf{R}$ with excess \textit{iso}-butylmagnesium bromide followed by treatment with ${\mathrm{H}}_3{\mathrm{O}}^{+}$ gives compound $\mathbf{S}$ as the major product. The total number of methyl ($-\mathrm{C}{\mathrm{H}}_3$) group(s) in compound $\mathbf{S}$ is ____.

   Show answer

   Answer: 6 or 12

3. Q482024 · 26 May 2024 · Paper 2· Numerical answer

   “PARAGRAPH I” An organic compound $\mathbf{P}$ with molecular formula ${\mathrm{C}}_9{\mathrm{H}}_{18}{\mathrm{O}}_2$ decolorizes bromine water and also shows positive iodoform test. $\mathbf{P}$ on ozonolysis followed by treatment with ${\mathrm{H}}_2{\mathrm{O}}_2$ gives $\mathbf{Q}$ and $\mathbf{R}$. While compound $\mathbf{Q}$ shows positive iodoform test, compound $\mathbf{R}$ does not give positive iodoform test. $\mathbf{Q}$ and $\mathbf{R}$ on oxidation with pyridinium chlorochromate (PCC) followed by heating give $\mathbf{S}$ and $\mathbf{T}$, respectively. Both $\mathbf{S}$ and $\mathbf{T}$ show positive iodoform test. Complete copolymerization of 500 moles of $\mathbf{Q}$ and 500 moles of $\mathbf{R}$ gives one mole of a single acyclic copolymer $\mathbf{U}$. [Given, atomic mass: H =1, C = 12, O =16] Sum of number of oxygen atoms in $\mathbf{S}$ and $\mathbf{T}$ is ____.

   Show answer

   Answer: 2 or 4

4. Q492024 · 26 May 2024 · Paper 2· Numerical answer

   “PARAGRAPH I” An organic compound $\mathbf{P}$ with molecular formula ${\mathrm{C}}_9{\mathrm{H}}_{18}{\mathrm{O}}_2$ decolorizes bromine water and also shows positive iodoform test. $\mathbf{P}$ on ozonolysis followed by treatment with ${\mathrm{H}}_2{\mathrm{O}}_2$ gives $\mathbf{Q}$ and $\mathbf{R}$. While compound $\mathbf{Q}$ shows positive iodoform test, compound $\mathbf{R}$ does not give positive iodoform test. $\mathbf{Q}$ and $\mathbf{R}$ on oxidation with pyridinium chlorochromate (PCC) followed by heating give $\mathbf{S}$ and $\mathbf{T}$, respectively. Both $\mathbf{S}$ and $\mathbf{T}$ show positive iodoform test. Complete copolymerization of 500 moles of $\mathbf{Q}$ and 500 moles of $\mathbf{R}$ gives one mole of a single acyclic copolymer $\mathbf{U}$. [Given, atomic mass: H =1, C = 12, O =16] The molecular weight of $\mathbf{U}$ is ____.

   Show answer

   Answer: 93018

5. Q502024 · 26 May 2024 · Paper 2· Numerical answer

   “PARAGRAPH II” When potassium iodide is added to an aqueous solution of potassium ferricyanide, a reversible reaction is observed in which a complex $\mathbf{P}$ is formed. In a strong acidic medium, the equilibrium shifts completely towards $\mathbf{P}$. Addition of zinc chloride to $\mathbf{P}$ in a slightly acidic medium results in a sparingly soluble complex $\mathbf{Q}$. The number of moles of potassium iodide required to produce two moles of $\mathbf{P}$ is ____.

   Show answer

   Answer: 2

6. Q512024 · 26 May 2024 · Paper 2· Numerical answer

   “PARAGRAPH II” When potassium iodide is added to an aqueous solution of potassium ferricyanide, a reversible reaction is observed in which a complex $\mathbf{P}$ is formed. In a strong acidic medium, the equilibrium shifts completely towards $\mathbf{P}$. Addition of zinc chloride to $\mathbf{P}$ in a slightly acidic medium results in a sparingly soluble complex $\mathbf{Q}$. The number of zinc ions present in the molecular formula of $\mathbf{Q}$ is ____.

   Show answer

   Answer: 2 or 3