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CHEMISTRY

Latest questions in this category.

45 questions

CHEMISTRY

What is the molality of a solution containing 5 g of urea (NHâ‚‚CONHâ‚‚) in 250 g of water? (Molar mass of urea = 60 g/m

Given: What is the molality of a solution containing 5 g of urea (NH₂CONH₂) in 250 g of water? (Molar mass of urea = 60 g/mol) These values define the system as per NCERT data. Formula: Moles = 5 / 60 = 0.0833 mol. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Mass of solvent = 0.25 kg. Molality = 0.0833 / 0.25 ≈ 0.333 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 of the following compounds is isostructural with KClOâ‚„ ?

KMnOâ‚„ forms crystals isostructural with KClOâ‚„, both having tetrahedral anions ( MnOâ‚„^- and ClOâ‚„^- ). 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

Which amine is formed when CH₃CH₂CH₂CH₂CONH₂ is treated with Br₂ and NaOH ?

Hoffmann bromamide reaction of pentanamide ( CH₃CH₂CH₂CH₂CONH₂ ) with Br₂/NaOH yields butan-1-amine ( CH₃CH₂CH₂CH₂NH₂ ) by losing one carbon. 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 compounds does not undergo the iodoform reaction?

The iodoform test is given by compounds containing the -COCH₃ group. Benzaldehyde lacks this group and does not give the test. 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 statements is true about ethers?

Ethers do not exhibit hydrogen bonding among themselves, resulting in lower boiling points compared to alcohols of similar molecular weight. 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

Which of the following is the correct IUPAC name of chloroform?

Chloroform’s IUPAC name is trichloromethane, as it contains three chlorine atoms attached to a single carbon atom. 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

Which ligand can form a chelate complex?

Câ‚‚Oâ‚„^{2- (oxalate) is bidentate, binding via two oxygen atoms to form a five-membered ring, making it a chelating ligand, unlike the unidentate options.

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 reaction involves the removal of an electropositive element as oxidation?

In 2K₄[Fe(CN)6] + H₂O₂ -> 2K₃[Fe(CN)6] + 2KOH, K is removed from K₄[Fe(CN)6], and Fe (+2 to +3) is oxidized. 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

The K_a of chloroacetic acid is 1.35 × 10⁻³. What is the pH of a 0.05 M solution?

Given: The K_a of chloroacetic acid is 1.35 × 10⁻³. What is the pH of a 0.05 M solution? These values define the system as per NCERT data. Formula: K_a = x²/0.05, 1.35 × 10⁻³= x²/0.05, x² = 6.75 × 10⁻⁵. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: x = sqrt6.75 × 10⁻⁵ approx 8.22 × 10⁻³, pH = -log(8.22 × 10⁻³) approx 2.09 . 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: Solutions, Topic: Concentration terms and colligative properties.

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CHEMISTRY

Which of the following elements is classified as an inner-transition element?

Inner-transition elements (f-block) include lanthanoids and actinoids. Cerium (Ce, Z=58) has 4f¹, placing it in the f-block. 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: p-Block, d and f Block Elements and Coordination Compounds, Topic: Properties of block elements and coordination chemistry.

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CHEMISTRY

Which of the following ions is a strong oxidizing agent with a standard electrode potential of +1.74 V?

Given: Which of the following ions is a strong oxidizing agent with a standard electrode potential of +1.74 V? These values define the system as per NCERT data. Formula: Ce^{4+ has E° = +1.74 V for Ce^{4+/Ce^{3+, making it a strong oxidant.. 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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