12th Chemistry Public Question Paper 2022 Key Questions

The 12th Chemistry public question paper for 2022 provides a diverse range of questions that assess students’ understanding of key concepts in Chemistry. This set includes theoretical, numerical, and application-based questions, designed to evaluate knowledge and problem-solving skills. Below are important questions and answers covering all types of topics from the syllabus.

Important Questions and Answers

Question: What is the octet rule in chemical bonding?

Answer: The octet rule states that atoms tend to gain, lose, or share electrons to attain a stable configuration of eight valence electrons in their outer shell.

Question: Define hybridization and its significance.

Answer: Hybridization is the mixing of atomic orbitals to form new hybrid orbitals, which have equivalent energy and shape. It explains the geometry of molecular structures.

Question: What is the difference between sigma and pi bonds?

Answer: A sigma bond is formed by the head-on overlap of orbitals, while a pi bond is formed by the sideways overlap of orbitals. Sigma bonds are stronger than pi bonds.

Question: Explain the concept of ionization energy.

Answer: Ionization energy is the energy required to remove an electron from an atom in its gaseous state to form a positive ion.

Question: What is Hess’s Law of constant heat summation?

Answer: Hess’s Law states that the total enthalpy change in a reaction is the same, regardless of the pathway taken, provided the initial and final conditions are the same.

Question: How is the rate of a chemical reaction defined?

Answer: The rate of a chemical reaction is the change in concentration of a reactant or product per unit time.

Question: What is a buffer solution?

Answer: A buffer solution is one that resists changes in pH when small amounts of an acid or base are added to it.

Question: Define electrochemical cell.

Answer: An electrochemical cell is a device that converts chemical energy into electrical energy through redox reactions.

Question: What is the importance of the equilibrium constant?

Answer: The equilibrium constant provides the ratio of the concentration of products to reactants at equilibrium and indicates the extent of a reaction.

Question: What is the difference between empirical and molecular formulas?

Answer: The empirical formula represents the simplest ratio of atoms in a compound, while the molecular formula represents the actual number of atoms of each element.

Question: Define the term “activation energy.”

Answer: Activation energy is the minimum energy required for a chemical reaction to occur.

Question: What is the role of a catalyst in a reaction?

Answer: A catalyst increases the rate of a chemical reaction by lowering the activation energy without being consumed in the reaction.

Question: Explain Le Chatelier’s Principle.

Answer: Le Chatelier’s Principle states that if a system at equilibrium is disturbed, the system will adjust to minimize the disturbance and restore equilibrium.

Question: What is an alloy? Give an example.

Answer: An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. Example: Brass (copper and zinc).

Question: What is the difference between crystalline and amorphous solids?

Answer: Crystalline solids have a regular, repeating arrangement of atoms, while amorphous solids lack a defined structure.

Question: Define molarity and normality.

Answer: Molarity is the number of moles of solute per liter of solution. Normality is the number of gram equivalents of solute per liter of solution.

Question: What are isotopes? Provide an example.

Answer: Isotopes are atoms of the same element with the same atomic number but different mass numbers. Example: Carbon-12 and Carbon-14.

Question: Explain the term “colligative properties.”

Answer: Colligative properties are properties of solutions that depend on the number of solute particles, not their identity, such as boiling point elevation and freezing point depression.

Question: What is the greenhouse effect?

Answer: The greenhouse effect is the trapping of heat in the Earth’s atmosphere due to the presence of greenhouse gases like carbon dioxide and methane.

Question: Explain the significance of the periodic table.

Answer: The periodic table organizes elements based on their properties and atomic structure, enabling prediction of element behavior and trends.

Question: What is a nucleophile and an electrophile?

Answer: A nucleophile is a species that donates an electron pair, while an electrophile is a species that accepts an electron pair.

Question: Define standard electrode potential.

Answer: Standard electrode potential is the potential difference between an electrode and its solution when the system is at standard conditions (1 M, 1 atm, 25°C).

Question: What are halogenated hydrocarbons?

Answer: Halogenated hydrocarbons are organic compounds containing one or more halogen atoms attached to a carbon chain.

Question: Describe the difference between thermoplastics and thermosetting plastics.

Answer: Thermoplastics can be reshaped by heating, while thermosetting plastics cannot be remolded after setting.

Question: What is Raoult’s law?

Answer: Raoult’s law states that the partial vapor pressure of a component in a solution is directly proportional to its mole fraction.

Question: What is the function of antioxidants in food?

Answer: Antioxidants prevent oxidation and spoilage of food by neutralizing free radicals.

Question: What are the types of adsorption?

Answer: Adsorption is of two types: physisorption (physical adsorption) and chemisorption (chemical adsorption).

Question: Explain the term “esterification.”

Answer: Esterification is the reaction of a carboxylic acid with an alcohol to form an ester and water.

Question: What is the difference between a primary and secondary alcohol?

Answer: A primary alcohol has the -OH group attached to a carbon bonded to only one other carbon, while a secondary alcohol is attached to a carbon bonded to two other carbons.

Question: Define corrosion and its prevention.

Answer: Corrosion is the deterioration of metals due to chemical reactions with their environment. Prevention methods include galvanization and coating.

Question: What is a polymer? Provide an example.

Answer: A polymer is a large molecule made of repeating units called monomers. Example: Polyethylene.

Question: Explain the significance of Gibbs free energy.

Answer: Gibbs free energy determines whether a process is spontaneous. A negative value indicates spontaneity.

Question: What are enantiomers?

Answer: Enantiomers are stereoisomers that are non-superimposable mirror images of each other.

Question: Define oxidation and reduction.

Answer: Oxidation is the loss of electrons, while reduction is the gain of electrons.

Question: What are aromatic compounds?

Answer: Aromatic compounds are organic molecules that contain a conjugated ring system and follow Huckel’s rule.

Question: What is saponification?

Answer: Saponification is the hydrolysis of fats or oils with an alkali to form soap and glycerol.

Question: Explain the term “enthalpy.”

Answer: Enthalpy is the heat content of a system at constant pressure.

Question: What are transition elements?

Answer: Transition elements are d-block elements that form compounds with partially filled d-orbitals.

Question: Define the term “alkali metals.”

Answer: Alkali metals are elements in Group 1 of the periodic table and are highly reactive.

The 12th Chemistry public question paper for 2022 encompasses a variety of questions, preparing students for examinations by covering theoretical and practical aspects. With clear explanations, it aids understanding and revision of key Chemistry concepts