Chemistry Question Bank Solution Class 11: Important Questions and Concepts

Class 11 Chemistry includes numerical problems, theoretical concepts, chemical calculations, and questions based on atomic structure and periodic properties. Students need to understand the underlying concepts and practise different question types to prepare for their examinations. Revising formulas, solving numerical questions, and understanding the reasons behind chemical trends are also important parts of preparation.

The Chemistry Question Bank Solution Class 11 session covers important questions from the GSHSEB Class 11 Chemistry question bank. The teacher discusses questions from three chapters:

Some Basic Concepts of Chemistry, Structure of Atom, and Classification of Elements and Periodicity. The session includes MCQs, numerical problems, theoretical questions, and explanations of important concepts. It also addresses students' doubts about the examination pattern and answer preparation.

Class 11 Chemistry Question Bank Solutions Overview

The question bank solution session focuses on important questions from three chapters of the GSHSEB Class 11 Chemistry Syllabus. It covers topics such as the mole concept, limiting reactants, atomic models, electronic configuration, quantum numbers, and periodic trends.

Along with solving objective questions, the teacher explains the methods used to approach numerical and theoretical problems. Students revise important formulas, understand the reasoning behind different chemical properties, and learn how to solve questions involving calculations.

Important Topics Covered in Class 11 Chemistry Question Bank

Here are chapter-wise important topics covered in the Class 11 Chemistry Question Bank:

Chapter 1: Some Basic Concepts of Chemistry 

This chapter covers questions related to the mole concept, molecular mass, percentage composition, limiting reactants, mole fraction, and laws of chemical combination.

Important Concepts and Explanations

• Same Number of Atoms: The number of moles in different substances is compared to determine which pair contains the same number of atoms.

• Mass Percentage of Carbon in Fructose: Fructose has the molecular formula C₆H₁₂O₆ and a molecular mass of 180 g/mol. The mass of carbon is calculated as 6 × 12 = 72 g. Its mass percentage is: (72/180)100, giving 40%.

• Limiting Reactant: In the reaction between hydrogen and chlorine to form HCl, the reactant consumed first is the limiting reactant. The amount of product formed depends on the quantity of this reactant.

• Mole Fraction of NaOH: The mole fraction of a solute in a 2 M aqueous NaOH solution is calculated by considering the moles of NaOH and water.

• Laws of Chemical Combination: The masses of elements combining in different oxides are compared to identify the applicable law, particularly the law of multiple proportions.

Chapter 2: Structure of Atom

This chapter covers atomic structure, electronic configuration, quantum numbers, and atomic models.

Important Concepts and Explanations

• Rutherford's Gold Foil Experiment: Most alpha particles passed straight through the gold foil because the nucleus occupies a very small region of the atom.

• Electronic Configuration of Chlorine: The number of electrons for which n + l = 3 is calculated using chlorine's electronic configuration and the relevant orbitals.

• Electronic Configuration of Transition Elements: Questions focus on identifying the correct electronic configuration of d-block elements.

• Principal Quantum Number: The relationship between the periodic number and the maximum principal quantum number is an important concept.

• Actinoids and Lanthanoids: Lanthanoids are associated with 4f orbitals, whereas actinoids are associated with 5f orbitals.

• Nickel Ion Formation: Nickel has an atomic number of 28 and an electronic configuration of [Ar] 3d⁸ 4s². Two electrons are removed from the 4s orbital to form Ni²⁺.

• Photon Energy and Wavelength: Energy and wavelength have an inverse relationship. The formula is: E=hc/. All wavelengths must be converted into the same unit before arranging them in ascending order of photon energy.

• Charge of One Mole of Protons: The total electric charge is calculated using the charge of a proton and Avogadro's number.

Chapter 3: Classification of Elements and Periodicity

This chapter covers periodic trends and important properties of elements.

Important Concepts and Explanations

• Elements Belonging to the Same Group: Aluminium and gallium belong to the same group based on their atomic numbers and positions in the periodic table.

• Valence Electrons: Elements in the same group generally have the same number of valence electrons, which explains their similar chemical properties.

• Chalcogens: Group 16 elements are called chalcogens or the oxygen family. Other important groups include halogens, noble gases, alkali metals and alkaline earth metals.

• Angular Nodes: The number of angular nodes is equal to the azimuthal quantum number (l). For a d orbital, l = 2, so it has two angular nodes.

• Ionisation Enthalpy: Ionisation enthalpy generally increases across a period. Exceptions include magnesium and aluminium, as well as nitrogen and oxygen.

• Electron Gain Enthalpy: Electron gain enthalpy generally becomes less negative down a group as atomic size increases.

• Neutral Oxides: Neutral oxides are identified by distinguishing them from acidic and basic oxides.

• Highest Ionisation Enthalpy: The positions of given elements in the periodic table are identified using their atomic numbers to compare their ionisation enthalpies.

• Atomic Size: Atomic size generally decreases across a period and increases down a group. This trend helps compare elements such as nitrogen and phosphorus.

• Highest Lattice Enthalpy: Lattice enthalpy depends on ionic charge and ionic size. When the charges are the same, smaller ions generally result in higher lattice enthalpy.

Important Theoretical Questions for Class 11 Chemistry

Apart from MCQs and numerical problems, use these theoretical questions that students should practise for their examinations. These include:

1. Draw the Lewis structures of H₂CO₃ and NO₂.

2. Explain why cations are smaller and anions are generally larger than their parent atoms.

3. Explain why the first ionisation enthalpy of beryllium is higher than that of boron.

4. Discuss the exceptions to the octet rule using BeCl₂ and PF₅.

5. Explain the dipole moment of SO₂ with reference to its molecular shape.

6. Compare the dipole moments of NH₃ and BF₃.

7. Explain why BCl₃ is a non-polar molecule despite having polar bonds.

Important Numerical Questions in Class 11 Chemistry

Use additional numerical problems that students should practise independently. These questions involve formula application, chemical calculations, and the interpretation of given data.

The important numerical topics include:

• Calculating the frequency and wavelength of photons emitted during electronic transitions in hydrogen.

• Calculating the products formed during the thermal decomposition of 200 g of CaCO₃.

• Determining the molar mass and molecular formula of a gas containing carbon and hydrogen using combustion data.

For the combustion-based question, use the method of solving the problem. Students need to use the given masses of carbon dioxide and water to calculate the masses of carbon and hydrogen. These values are then converted into mole ratios to determine the empirical formula. The empirical formula and molar mass are used to calculate the molecular formula.

How the Question Bank Solutions Help in Revision

Solving questions from different chapters helps students revisit important concepts and understand how to approach objective, theoretical, and numerical problems. The session covers the following areas for revision:

• Conceptual understanding: Questions on mole concepts, atomic structure, and periodicity help students revise the fundamental concepts of Class 11 Chemistry.

• Numerical practice: Problems involving molecular mass, limiting reactants, photon energy, and chemical composition help students practise formula-based calculations.

• Periodic trends: Questions on ionisation enthalpy, electron gain enthalpy, atomic size and lattice enthalpy help revise the properties of elements.

• Theoretical preparation: Topics such as Lewis structures, the octet rule and molecular polarity help students practise explanation-based questions.

• Doubt clarification: The teacher addresses questions related to the paper pattern and explains the methods used to solve different problems.

The GSHSEB Exam Class 11 Chemistry question bank solution session covers important questions from Some Basic Concepts of Chemistry, Structure of Atom, and Classification of Elements and Periodicity. It includes MCQs, numerical problems, theoretical questions, and explanations of important formulas and concepts.

Students can use these solutions to revise the chapters, practise numerical questions, and strengthen their understanding of important Chemistry concepts. They can also refer to the GSHSEB Class 11 batches by Physics Wallah for additional preparation support and relevant learning resources.