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CHEMISTRY

Latest questions in this category.

45 questions

CHEMISTRY

What is the molality of a solution containing 8 g of NaOH in 400 g of water? (Molar mass of NaOH = 40 g/mol)

Given: What is the molality of a solution containing 8 g of NaOH in 400 g of water? (Molar mass of NaOH = 40 g/mol) These values define the system as per NCERT data. Formula: Moles = 8 / 40 = 0.2 mol. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Mass of solvent = 0.4 kg. Molality = 0.2 / 0.4 = 0.5 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 amines reacts with CH₃COCl to form an amide?

Primary amines like CH₃CH₂NH₂ react with acetyl chloride ( CH₃COCl ) to form amides ( CH₃CONHCH₂CH₃ ), while tertiary amines do not. 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

How many grams of ethylene glycol ( C₂H₆O₂ ) are required to depress the freezing point of 300 g of water by 1.24

Given: How many grams of ethylene glycol ( C₂H₆O₂ ) are required to depress the freezing point of 300 g of water by 1.24 K? ( K_f = 1.86 K kg/mol, Molar mass of ethylene glycol = 62 g/mol ) These values define the system as per NCERT data. Formula: Δ T_f = K_f · m. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: 1.24 = 1.86 · m, m = 0.667 mol/kg . Moles = 0.667 × 0.3 = 0.2 mol . Mass = 0.2 × 62 = 12.4 g . 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 vitamins is also known as ascorbic acid?

Vitamin C, a water-soluble vitamin, is chemically known as ascorbic acid and prevents scurvy by aiding collagen synthesis. 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

What is the product when (CH₃)2NH reacts with HNO₂ ?

Given: What is the product when (CH₃)2NH reacts with HNO₂ ? These values define the system as per NCERT data. Formula: Secondary amines like (CH₃)2NH react with HNO₂ to form yellow oily N-nitrosoamines, (CH₃)2N-N=O, without gas evolution.. 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

Which reaction is used to introduce an -OH group at the ortho position of phenol?

Kolbe’s reaction involves the reaction of sodium phenoxide with CO ₂ to introduce an -OH group at the ortho position. 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

What is the hybridization of the carbon atom in an allylic halide?

In allylic halides, the halogen is attached to an sp3-hybridized carbon adjacent to a carbon-carbon double bond. 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 gas has a solubility of 0.015 mol/L in water at a partial pressure of 3 bar at 298 K. What is the Henry's law constant

Given: A gas has a solubility of 0.015 mol/L in water at a partial pressure of 3 bar at 298 K. What is the Henry's law constant ( K_H ) in bar? These values define the system as per NCERT data. Formula: Henry's law: p = K_H · solubility (in molarity). This is the standard NCERT relation for this phenomenon. Substitution & Calculation: K_H = fracpsolubility = 3/0.015 = 200 bar . 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

Which of the following compounds will show geometrical isomerism?

Alkenes of the type C=C with two different groups attached to each carbon exhibit geometrical isomerism. 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

For N₂(g) + 3H₂(g) 2NH₃(g), removing NH₃ will:

By Le Chatelier’s principle, removing NH₃ shifts the equilibrium to the right to produce more NH₃ . 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 hydrides is formed by a Group 15 element?

Given: Which of the following hydrides is formed by a Group 15 element? These values define the system as per NCERT data. Formula: Group 15 elements (ns²np³) form hydrides like NH₃ (nitrogen), unlike Group 1 (LiH), Group 2 (MgH₂), or Group 14 (CH₄).. 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: 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 statements about alcohols is incorrect?

Alcohols are generally more acidic than water, but the presence of alkyl groups reduces acidity. 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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