CHEMISTRY

CHEMISTRY

Which amine can be synthesized from CH₃CH₂CH₂Br using Gabriel phthalimide synthesis?

Gabriel phthalimide synthesis converts primary alkyl halides like CH₃CH₂CH₂Br to primary amines, yielding CH₃CH₂CH₂NH₂ (propan-1-amine). 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 complex produces 1 mole of AgCl per mole when treated with excess AgNO₃ ?

[CoCl₂(NH₃)4]Cl has one ionizable Cl^- outside the coordination sphere, yielding 1 mole of AgCl, while the two inside are non-ionizable. 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 oxidation number of oxygen in OF₂ ?

In OF₂, F is -1 (more electronegative), sum is zero: x + 2(-1) = 0, x - 2 = 0, x = +2 . 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 oxidation state of cobalt in CoCl₂ is:

In CoCl₂, Cl = -1 (2 chlorines = -2). For neutrality, Co = +2. 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 oxidation state of cobalt in [Co(en)2Cl₂]Cl ?

Given: What is the oxidation state of cobalt in [Co(en)2Cl₂]Cl ? Formula: The complex charge is +1 (balanced by 1 Cl⁻), so Co’s oxidation state is x - 2 = +1, x = +3 .. Substitution & Calculation: In [Co(en)2Cl₂]+, 2 en are neutral, 2 Cl^- contribute -2. 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), Chapter: Electrochemistry (Latest NCERT 2026-27), Topic: Faraday's laws, charge required to reduce Al³⁺, 3F = 3 × 96500 C

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CHEMISTRY

What is the oxidation state of chromium in the dichromate ion Cr₂O₇^{2- ?

Given: What is the oxidation state of chromium in the dichromate ion Cr₂O₇^{2- ? Formula: In Cr₂O₇^{2-, O = -2 (7 oxygens = -14). Substitution & Calculation: Let Cr = x. Then, 2x - 14 = -2, so 2x = 12, x = +6 . 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

A reaction follows Rate = k[A][B]² with k = 0.1 L² mol^{-2 s^{-1, [A] = 0.2 M, and [B] = 0.4 M. What is the rate in mol

Given: A reaction follows Rate = k[A][B]² with k = 0.1 L² mol^{-2 s^{-1, [A] = 0.2 M, and [B] = 0.4 M. What is the rate in mol L^{-1 s^{-1 ? Formula: Rate = k[A][B]² = 0.1 × 0.2 × (0.4)² = 0.1 × 0.2 × 0.16 = 0.0032 .. Substitution: Substituting given values into formula as per NCERT 2026-27 method. Calculation: Simplifying step by step with proper SI units like m/s², J kg⁻¹ K⁻¹, 10⁻⁵, A m⁻¹ etc. 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

Calculate the boiling point elevation of a solution containing 9 g of urea ( NH₂CONH₂ ) in 200 g of water. ( K_b = 0.52

Given: Calculate the boiling point elevation of a solution containing 9 g of urea ( NH₂CONH₂ ) in 200 g of water. ( K_b = 0.52 K kg/mol, Molar mass of urea = 60 g/mol ) Formula: Moles of urea = 9/60 = 0.15 mol. Substitution & Calculation: Molality = 0.15/0.2 = 0.75 mol/kg . Δ T_b = 0.52 × 0.75 = 0.39 K . 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), Chapter: Solutions (Latest NCERT 2026-27), Topic: Colligative properties, ΔT_b = K_b·m, urea NH₂CONH₂ example

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CHEMISTRY

For 2NO₂(g) N₂(g) + 2O₂(g), K_c = 0.25 at 600 K. If initial [NO₂] = 0.4 M, what is [O₂] at equilibrium?

Given: For 2NO₂(g) N₂(g) + 2O₂(g), K_c = 0.25 at 600 K. If initial [NO₂] = 0.4 M, what is [O₂] at equilibrium? Formula: Let [N₂] = x, [O₂] = 2x, [NO₂] = 0.4 - 2x. Substitution & Calculation: K_c = frac[N₂][O₂]²[NO₂]² = x (2x)²/(0.4 - 2x)² = 0.25 . 4x³/(0.4 - 2x)² = 0.25, solve: x approx 0.05, 2x = 0.1 M. 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 standard ll potential for a galvanic ll where Sn(s) is oxidized to Sn²⁺(aq) and Cu²⁺(aq) is reduced to Cu(s)

Given: What is the standard ll potential for a galvanic ll where Sn(s) is oxidized to Sn²⁺(aq) and Cu²⁺(aq) is reduced to Cu(s), given their standard reduction potentials are -0.14 V and 0.34 V respectively? Formula: E_{ll⁰ = E_{cathode⁰ - E_{anode⁰. Substitution & Calculation: For Sn(s) → Sn²⁺(aq) + 2e⁻ (anode) and Cu²⁺(aq) + 2e⁻ → Cu(s) (cathode): E_{ll⁰ = 0.34 - (-0.14) = 0.48 V . 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 K_p for H₂(g) + CO₂(g) H₂O(g) + CO(g) is 0.25 at 1000 K. What is K_c if R = 0.0821 L · atm · mol^{-1 · K^{-1 ?

Given: The K_p for H₂(g) + CO₂(g) H₂O(g) + CO(g) is 0.25 at 1000 K. What is K_c if R = 0.0821 L · atm · mol^{-1 · K^{-1 ? Formula: Δ n = (1 + 1) - (1 + 1) = 0, so K_p = K_c (RT)^{Δ n = K_c. Substitution & Calculation: Thus, K_c = K_p = 0.25 . 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 EMF of a ll with Fe(s) | Fe²⁺(0.01 M) || H⁺(1 M) | H₂(g, 1 bar) | Pt(s) at 298 K, given E_{Fe^{2+/Fe⁰ = -0.4

Given: What is the EMF of a ll with Fe(s) | Fe²⁺(0.01 M) || H⁺(1 M) | H₂(g, 1 bar) | Pt(s) at 298 K, given E_{Fe^{2+/Fe⁰ = -0.44 V and E_{H^{+/H_2⁰ = 0 V ? Formula: E_{ll⁰ = 0 - (-0.44) = 0.44 V, n = 2. Substitution & Calculation: E_{ll = E_{ll⁰ - 0.059/2 log frac[Fe^{2+][H^{+]² . Q = 0.01/1² = 0.01, log Q = -2 . E_{ll = 0.44 - 0.059/2 × (-2) = 0.44 + 0.059 = 0.499 V approx 0.50 V . 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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