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CHEMISTRY

Latest questions in this category.

45 questions

CHEMISTRY

For 2SO₃(g) 2SO₂(g) + O₂(g), adding an inert gas at constant pressure will:

Given: For 2SO₃(g) 2SO₂(g) + O₂(g), adding an inert gas at constant pressure will: These values define the system as per NCERT data. Formula: Δ n = (2 + 1) - 2 = 1. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: At constant pressure, adding an inert gas increases volume, shifting to products (more moles). Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.

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CHEMISTRY

The purple color of MnOâ‚„^- ion is attributed to which phenomenon?

The intense purple color of MnOâ‚„^- results from charge transfer from oxygen p orbitals to manganese d orbitals, not d-d transitions. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Relevant Chemistry topic covering principles and examples as per NCERT.

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CHEMISTRY

The electron gain enthalpy of oxygen is less negative than sulfur because:

Oxygen’s smaller 2p orbitals experience greater electron repulsion when an electron is added compared to sulfur’s 3p orbitals. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Thermodynamics, Equilibrium and Chemical Kinetics, Topic: Energetics, equilibrium constants and reaction rates.

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CHEMISTRY

The hormone that stimulates milk ejection is:

Oxytocin, released from the posterior pituitary, triggers milk ejection by contracting myoepithelial lls in the mammary glands. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Relevant Chemistry topic covering principles and examples as per NCERT.

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CHEMISTRY

Which of the following conditions favors the oxidation of alkanes to alcohols?

Controlled oxidation of alkanes in the presence of a catalyst like KMnOâ‚„ leads to the formation of alcohols. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.

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CHEMISTRY

A first-order reaction has a rate constant of 0.01386 min^{-1 . What percentage of the reactant remains after 100 minute

Given: A first-order reaction has a rate constant of 0.01386 min^{-1 . What percentage of the reactant remains after 100 minutes? These values define the system as per NCERT data. Formula: ln frac[R]_0[R] = k t = 0.01386 × 100 = 1.386. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: frac[R][R]_0 = e^{-1.386 = 0.25, so 25% remains. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Relevant Chemistry topic covering principles and examples as per NCERT.

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CHEMISTRY

A solution has a density of 1.22 g/mL and contains 35% by mass Hâ‚‚SOâ‚„. What is its molarity? (Molar mass of Hâ‚‚SOâ‚„

Given: A solution has a density of 1.22 g/mL and contains 35% by mass H₂SO₄. What is its molarity? (Molar mass of H₂SO₄ = 98 g/mol) These values define the system as per NCERT data. Formula: H₂SO₄ = 35 g. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Assume 100 g solution. . Moles = 35 / 98 ≈ 0.3571 mol. Volume = 100 / 1.22 ≈ 81.97 mL = 0.08197 L. Molarity = 0.3571 / 0.08197 ≈ 4.36 M ≈ 4.4 M. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.

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CHEMISTRY

Which reagent is used for the selective reduction of carboxylic acids to aldehydes?

DIBAL-H (Diisobutylaluminium hydride) is used for the selective reduction of carboxylic acids and esters to aldehydes. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.

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CHEMISTRY

A first-order reaction has a rate constant of 0.01732 min^{-1 . What is the half-life in minutes?

Given: A first-order reaction has a rate constant of 0.01732 min^{-1 . What is the half-life in minutes? These values define the system as per NCERT data. Formula: t_{1/2 = 0.693/k = 0.693/0.01732 = 40 min .. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Substituting values like 1.2 × 10⁻⁵, 236 J kg⁻¹ K⁻¹, CH₃CH₂NH₂ etc. into the formula and simplifying step by step. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Relevant Chemistry topic covering principles and examples as per NCERT.

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CHEMISTRY

In which compound does the ntral atom exhibit an expanded octet?

In SF₆, sulfur has 12 electrons around it (6 bonds), exceeding the octet, possible due to 3d orbitals. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.

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