Chemistry Practice Paper 2022-23 Class 12

Questions and Answers

What should candidates ensure before they start answering questions on the paper?

That they leave some pages blank

That their roll number is in the answer-book

That the question paper is correct and complete (correct)

That they have their answer-book ready

How many printed pages should the question paper contain?

13 (correct)

What action must be taken before answering a question according to the instructions?

Write the question's Serial Number (correct)

Draw diagrams wherever necessary

Underline the key concepts

What will happen if a candidate makes a claim about the question paper after the examination?

No claims will be entertained Signup and view all the answers

What should candidates do if they require additional space for their answers?

None will be provided; use the answer-book only Signup and view all the answers

What must candidates write on the question paper?

Their roll number Signup and view all the answers

How many questions does the question paper have?

20 Signup and view all the answers

What instruction is given regarding blank pages in the answer-book?

No blank page/pages should be left Signup and view all the answers

How many total questions are present in the paper?

20 Signup and view all the answers

What type of questions does Section A consist of?

Multiple choice type questions Signup and view all the answers

What is the mark distribution for questions in Section C?

3 marks each Signup and view all the answers

Which section contains internal choice questions?

Section D Signup and view all the answers

Which segment of the question paper includes two marks questions?

Section B Signup and view all the answers

For how many questions does each answer from (vi) to (xiv) allow one or two-word responses?

15 questions Signup and view all the answers

What is the maximum mark allotted for each question in Section D?

5 marks each Signup and view all the answers

How many sections is the paper divided into?

4 sections Signup and view all the answers

Which type of questions are included in Section B of the question paper?

Very short answer type questions Signup and view all the answers

Which of the following is not a section in the question paper?

Section E Signup and view all the answers

What is the boiling point of water when 18 g of glucose is dissolved in 1 kg of water at 1.013 bar?

101.20 °C Signup and view all the answers

How long will it take for a first order reaction with a rate constant of 1.15 × 10-3 s-1 to reduce 5 g of reactant to 3 g?

1219.04 s Signup and view all the answers

According to Faraday’s first law of electrolysis, what is directly proportional to the amount of substance deposited?

The charge passed through the electrolyte Signup and view all the answers

What defines the Wurtz reaction?

Coupling of alkyl halides in the presence of sodium Signup and view all the answers

Lanthanoid contraction primarily affects which of the following properties of elements?

Atomic radius Signup and view all the answers

What is the main reason phenol is more acidic than alcohol?

Phenol can stabilize its negative charge with resonance Signup and view all the answers

Which statement correctly describes a characteristic of a facial isomer?

It has different spatial arrangements affecting reactivity. Signup and view all the answers

Which method is appropriate for identifying primary amines?

Acylation followed by hydrolysis Signup and view all the answers

What is the result of the Swarts reaction?

Formation of perfluorinated compounds Signup and view all the answers

What characterizes a pseudo first order reaction?

It involves two reactants where one is in excess. Signup and view all the answers

Why are haloarenes resistant to nucleophilic substitution?

The aromatic ring stabilizes the bond to the leaving group. Signup and view all the answers

Which acid from the pair CH3COOH and CH2FCOOH is expected to be stronger?

CH2FCOOH due to the electron-withdrawing effect of fluorine. Signup and view all the answers

What defines osmotic pressure?

It is directly proportional to the solute concentration. Signup and view all the answers

What is the IUPAC name of [Co(NH3)6]Cl?

Ammoniacobalt(III) chloride Signup and view all the answers

Why does the pK of aniline exceed that of methylamine?

Aniline is less basic due to reduced electron donation. Signup and view all the answers

Which vitamins are classified as fat-soluble?

Vitamin A and Vitamin D Signup and view all the answers

What is the primary reason for the stability of Mn2+ compounds compared to Fe2+ in higher oxidation states?

Mn2+ has a half-filled d-orbital configuration. Signup and view all the answers

Which characteristic best explains a peptide linkage?

It occurs between carboxyl and amino groups. Signup and view all the answers

How would one apply Henry's law practically?

To calculate gas solubility in liquids. Signup and view all the answers

What is the product when Benzoic acid is converted to m-Nitrobenzyl alcohol?

m-Nitrobenzyl alcohol Signup and view all the answers

What is the correct reaction product for the conversion of Benzaldehyde to Benzophenone?

Benzophenone Signup and view all the answers

Which process describes the reaction involving the formation of an enolate from a carbonyl compound followed by a reaction with another carbonyl compound?

Aldol condensation Signup and view all the answers

What is the outcome of the given reaction: $C_2H_5OH + CH_3COCl \rightarrow$?

Ethyl acetate Signup and view all the answers

Which statement correctly describes the Nernst equation?

It relates the cell potential to the reaction quotient. Signup and view all the answers

What does the standard cell potential represent in an electrochemical cell?

The voltage produced under standard conditions at 25°C. Signup and view all the answers

For the reaction $Zn + 2Ag^+ \rightarrow Zn^{2+} + 2Ag$, what is the standard cell potential calculated?

0.76 V Signup and view all the answers

What defines the working principle of the standard hydrogen electrode?

It uses hydrogen ions with a platinum electrode. Signup and view all the answers

When 0.5 amperes of current flows through a wire for 2 hours, how many electrons flow through it?

4.8 x 10^20 electrons Signup and view all the answers

Which of the following does NOT describe decarboxylation?

It always produces an aldehyde as a product. Signup and view all the answers

Study Notes

Exam Overview

The exam is for 12th grade students, specifically in Chemistry.
Total duration is 3 hours and the maximum score is 70 marks.
It consists of 20 questions divided into four sections: A, B, C, and D.

General Instructions

All questions are compulsory.
The question paper has a total of 20 questions organized into four sections with different types of questions.
Section A includes 15 objective type questions with various formats, including multiple-choice.
Sections B, C, and D contain very short, short, and long answer type questions respectively.
Ensure correct and complete question paper before starting; no claims will be entertained afterward.

Section A - Objective Type Questions

Question Format: 1 mark each for multiple-choice and one or two-word answers.
Topics: Questions may include definitions, reactions, and laws related to Chemistry concepts.
Example questions could cover definitions (e.g., "What is pseudo first order reaction?") and applications of laws (e.g., "One application of Henry’s law").

Section B - Very Short Answer Type Questions

Question Format: 2 marks each.
Topics typically involve explanations of concepts like nucleophilic substitution and strength comparison of acids.
Questions may ask students to provide IUPAC names for given compounds or to explain observations about chemical properties (e.g., why aniline has a higher pK than methylamine).

Section C - Short Answer Type Questions

Question Format: 3 marks each.
Focus on applied concepts and calculations, such as changes in boiling point due to solutes and determining time taken for reactions.
Questions may require elaboration on specific chemical reactions or phenomena, such as Faraday's laws or identifying functional groups.

Section D - Long Answer Type Questions

Question Format: 5 marks each.
Emphasis on detailed explanations and chemical equations.
Students could be asked to perform conversions between different organic compounds, describe reaction mechanisms, or derive important equations like Nernst's equation.
May involve drawing structural representations or explaining concepts such as lanthanoid contraction and its effects.

Key Topics Covered

Chemical Reaction Types: Understanding pseudo first-order reactions, nucleophilic substitutions, and electrolysis.
Organic Chemistry: Reactions like Wurtz, Sandmeyer, and Aldol condensation; identification of amines and acids.
Inorganic Chemistry: IUPAC naming conventions and structural isomers.
Physical Chemistry: Concepts including osmotic pressure as a colligative property and Nernst equation for electrochemical cells.

Practical Applications

Understanding real-world applications of chemical laws and principles in experimental and theoretical scenarios.
Evaluating the stability of compounds and predicting outcomes based on structural differences.
Conducting stoichiometric calculations to gauge reaction progress and yields.

Tips for Preparation

Review definitions and key concepts in organic, inorganic, and physical chemistry.
Practice writing and balancing reactions.
Familiarize with chemical equations and their implications.
Solve past paper questions to understand exam format and expectations.

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Description

This practice paper is designed for 12th-grade students studying Chemistry in both Hindi and English mediums. It includes a variety of questions to help students prepare for their academic assessments. Time allowed for the quiz is 3 hours, with a maximum score of 70 marks.