CHEMISTRY

CHEMISTRY

How many grams of NO are produced from 63 g of HNO₃ in 3HNO₃ + P -> H₃PO₃ + 3NO ? (Molar masses: HNO₃ = 63, NO = 30)

Given: How many grams of NO are produced from 63 g of HNO₃ in 3HNO₃ + P -> H₃PO₃ + 3NO ? (Molar masses: HNO₃ = 63, NO = 30) Formula: Moles of HNO₃ = 63 / 63 = 1. Substitution & Calculation: 3 moles HNO₃ produce 3 moles NO, so 1 mole produces 1 mole = 1 × 30 = 30 g. Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

The ionic radius of Cr^{3+ in the 3d series is approximately:

From the PDF, the ionic radius of Cr^{3+ is 62 pm, decreasing across the series due to increased nuclear charge. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII), Chapter: Electrochemistry (Latest NCERT 2026-27), Topic: Faraday's laws, charge required to reduce Al³⁺, 3F = 3 × 96500 C

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CHEMISTRY

Which of the following methods is used for the industrial preparation of ethyne?

Ethyne is industrially prepared by treating calcium carbide with water. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

Which compound is obtained when benzaldehyde is treated with Fehling’s solution?

Benzaldehyde does not give Fehling’s test as it cannot reduce Fehling’s solution. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

What is the formal charge on the carbon atom in the CO₃²- ion in one of its resonance structures?

In one resonance structure of CO₃²-, carbon has 1 double bond (4 electrons) and 2 single bonds (4 electrons). Formal charge = 4 - 0 - 1/2 × 8 = 0. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII), Chapter: Electrochemistry (Latest NCERT 2026-27), Topic: Faraday's laws, charge required to reduce Al³⁺, 3F = 3 × 96500 C

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CHEMISTRY

For the reaction 2P + Q -> 3R, the rate of disappearance of Q is 1.5 × 10⁻³mol L^{-1 s^{-1 . What is the rate of formati

Given: For the reaction 2P + Q -> 3R, the rate of disappearance of Q is 1.5 × 10⁻³mol L^{-1 s^{-1 . What is the rate of formation of R? Formula: Rate = -1/2 fracΔ[P]Δ t = -fracΔ[Q]Δ t = 1/3 fracΔ[R]Δ t. Substitution & Calculation: -fracΔ[Q]Δ t = 1.5 × 10⁻³, so fracΔ[R]Δ t = 3 × 1.5 × 10⁻³= 4.5 × 10⁻³. Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

What is the mass percentage of sulfur in Na₂S? (Atomic masses: Na = 23, S = 32)

Given: What is the mass percentage of sulfur in Na₂S? (Atomic masses: Na = 23, S = 32) Formula: Molar mass = (2 × 23) + 32 = 46 + 32 = 78 g/mol. Substitution & Calculation: Mass of S = 32 g. % S = (32 / 78) × 100 ≈ 41.03%. Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

The vapor pressure of pure water at 298 K is 23.8 mm Hg. What is the vapor pressure of a solution containing 18 g of suc

Given: The vapor pressure of pure water at 298 K is 23.8 mm Hg. What is the vapor pressure of a solution containing 18 g of sucrose ( C₁₂H₂₂O₁₁ ) in 162 g of water? (Molar mass: C₁₂H₂₂O₁₁ = 342 g/mol ) Formula: Moles of sucrose = 18/342 = 0.0526 mol. Substitution & Calculation: Moles of water = 162/18 = 9 mol . Mole fraction of water = 9/9 + 0.0526 = 0.994 . Vapor pressure = 0.994 × 23.8 = 23.66 mm Hg . Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

How many optical isomers are possible for [PtCl₂(en)2]^{2+ ?

The cis isomer of [PtCl₂(en)2]^{2+ (square planar) is chiral due to two bidentate en ligands, forming 2 optical isomers (d and l). This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

The general outer electronic configuration of transition elements is:

d-block elements (Groups 3-12) have the configuration (n-1)d¹⁻¹⁰ns⁰⁻², reflecting filling of d-orbitals. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

Which of the following aldehydes undergoes the Cannizzaro reaction?

The Cannizzaro reaction occurs in aldehydes that lack α-hydrogen atoms. Benzaldehyde does not have an α-hydrogen, so it undergoes this reaction. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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CHEMISTRY

What is the approximate ratio of the radius of an atom to its nucleus?

Rutherford’s model states the atomic radius is about 10⁻¹⁰m and the nuclear radius is 10⁻¹⁵m, giving a ratio of 10⁻¹⁰/ 10⁻¹⁵= __10POW₅__. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.

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