CHEMISTRY

CHEMISTRY

What is the mass percentage of nitrogen in NH₄NO₃? (Atomic masses: N = 14, H = 1, O = 16)

Given: What is the mass percentage of nitrogen in NH₄NO₃? (Atomic masses: N = 14, H = 1, O = 16) Formula: Molar mass = (2 × 14) + (4 × 1) + (3 × 16) = 28 + 4 + 48 = 80 g/mol. Substitution & Calculation: Mass of N = 28 g. % N = (28 / 80) × 100 = 35%. 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: Chemical Bonding (Latest NCERT 2026-27), Topic: Hybridization of nitrogen in CH₃NH₂, sp³ hybridization and pyramidal geometry

View Details

CHEMISTRY

Which element has the lowest electron gain enthalpy in Group 15?

Bismuth (Bi), at the bottom of Group 15, has the least negative electron gain enthalpy due to its large size reducing electron attraction. 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.

View Details

CHEMISTRY

Which of the following compounds does not give a positive iodoform test?

The iodoform test is given by compounds containing the CH ₃ -C=O or CH ₃ -CHOH groups. 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.

View Details

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.

View Details

CHEMISTRY

Hess’s law is a consequence of which thermodynamic principle?

Hess’s law states that enthalpy change is path-independent, a result of enthalpy being a state function. 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.

View Details

CHEMISTRY

Which compound is obtained when benzophenone is reduced using Zn-Hg/HCl?

Clemmensen reduction of benzophenone using Zn-Hg/HCl reduces the carbonyl group to a methylene (-CH₂-) group, forming diphenylmethane. 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.

View Details

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.

View Details

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.

View Details

CHEMISTRY

What is the mass percentage of oxygen in NaNO₃? (Atomic masses: Na = 23, N = 14, O = 16)

Given: What is the mass percentage of oxygen in NaNO₃? (Atomic masses: Na = 23, N = 14, O = 16) Formula: Molar mass = 23 + 14 + (3 × 16) = 23 + 14 + 48 = 85 g/mol. Substitution & Calculation: Mass of O = 48 g. % O = (48 / 85) × 100 ≈ 56.47%. 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.

View Details

CHEMISTRY

What is the bond angle in the C₂H₂ molecule around the carbon atoms?

C₂H₂ has a triple bond between carbons, each bonded to one hydrogen, with no lone pairs, resulting in a linear shape with a bond angle of 180°. 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.

View Details

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.

View Details

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

View Details