Important Questions Class 12 Chemistry Chapter 5: Coordination Compounds
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The study of important questions Class 12 chemistry chapter 5 is important for students who preparing for board exams and competitive tests like NEET or JEE. As class 12th board is approaching, preparation of this topic becomes more important. This chapter, Coordination Compounds class 12 chemistry important question sets, focuses on how central metal ions form complexes with surrounding molecules or ions known as ligands. Understanding these interactions is fundamental to grasping biological processes (like chlorophyll and hemoglobin) and industrial catalysis.
Key Concepts in Coordination Compounds
Before diving into the questions, it is important to understand the structural and bonding aspects that define these compounds.
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Central Metal Ion: The metal atom or ion to which a fixed number of ions or groups are attached.
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Ligands: Ions or neutral molecules that bond to the central metal. A multidentate ligand (like EDTA) can bind through multiple donor atoms.
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Coordination Number: The total number of points at which ligands are attached to the central metal ion.
Coordination Compounds Class 12 Important Questions (MCQs)
Test your knowledge with these class 12 chemistry Coordination Compounds mcq samples derived from standard practice papers.
I. Solutions & Colligative Properties
Q: Calculate the mole fraction of glycerine C3H5(OH)3 in a solution containing 36g water and 46g glycerine. A: 0.20.
Q: Define Osmotic Pressure. A: The excess pressure that must be applied to the solution side to prevent the flow of solvent through a semi-permeable membrane.
Q: Calculate the osmotic pressure of a protein solution (1.25g in 1L) at 300K with molar mass 1.2×103g/mol. A: 0.026 bar (using π=CRT).
Q: What is reverse osmosis? A: The process where solvent flows from solution to pure solvent when pressure higher than osmotic pressure is applied.
Q: Define molal depression constant (Kf). A: It is the depression in freezing point for a 1 molal solution.
Q: State Henry’s Law. A: The solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
Q: Give two applications of Henry’s Law. A: (1) Carbonated beverages (soda water) and (2) Deep-sea diving (preventing 'bends').
Q: What are minimum boiling azeotropes? A: Solutions showing large positive deviation from Raoult's law that boil at a lower temperature than either component (e.g., 95% Ethanol).
Q: What is the Van’t Hoff factor (i) for KCl? A: 2 (due to dissociation into K+ and Cl−).
Q: Which is true for an ideal solution? A: ΔHmix=0 and ΔVmix=0.
II. Electrochemistry
Q: What is the charge of one mole of electrons? A: 96500 C (1 Faraday).
Q: Calculate ΔG∘ for a Daniel cell where E∘=1.1V. A: -212.3 kJ/mol.
Q: State Kohlrausch's Law. A: The limiting molar conductivity of an electrolyte is the sum of the individual contributions of its anions and cations.
Q: Why does conductivity decrease with dilution? A: Because the number of ions per unit volume decreases.
Q: Explain the working of H2−O2 fuel cell. A: It uses the reaction of H2 and O2 to form water, producing electricity with high efficiency and zero emissions.
III. Chemical Kinetics
Q: What is the unit of the rate constant for a first-order reaction? A: s−1.
Q: Define the half-life of a reaction. A: The time required for the reactant concentration to decrease to half its initial value.
Q: What are pseudo-first-order reactions? A: Higher-order reactions that behave as first-order due to one reactant being in large excess (e.g., hydrolysis of ester).
Q: Write the Arrhenius Equation. A: k=A⋅e−Ea/RT.
IV. d and f-Block Elements
Q: What is the common oxidation state for Lanthanides? A: +3.
Q: What is Lanthanide Contraction? A: The progressive decrease in atomic and ionic radii with increasing atomic number in the lanthanide series.
Q: Why are transition elements good catalysts? A: Due to their ability to adopt multiple oxidation states and provide a large surface area for reactions.
V. Coordination Chemistry
Q: What is a multidentate ligand? A: A ligand that can bond to a metal through multiple donor atoms (e.g., EDTA).
Q: Identify the coordination number of [Cr(NH3)4Cl2]Br. A: 6.
Q: Give the IUPAC name for K4[Fe(CN)6]. A: Potassium hexacyanoferrate(II).
Q: Which isomer of [Pt(NH3)2Cl2] is used in cancer treatment? A: Cis-platin (cis-isomer).
VI. Organic Chemistry
Q: State Saytzeff Rule. A: In dehydrohalogenation, the preferred product is the alkene with the greater number of alkyl groups attached to the doubly bonded carbon atoms.
Q: What is the Reimer-Tiemann reaction? A: Reaction of phenol with chloroform and sodium hydroxide to produce salicylaldehyde.
Q: What is Gabriel Phthalimide Synthesis used for? A: Preparation of primary aliphatic amines.
VII. Biomolecules
Q: Which of the following is a polysaccharide? A: Cellulose.
Q: What are essential amino acids? A: Amino acids that cannot be synthesized by the body and must be obtained from diet (e.g., Lysine).
Q: Explain the denaturation of protein. A: Loss of biological activity due to physical (temp) or chemical (pH) changes that disrupt its structure.
Q: Which vitamin is responsible for blood clotting? A: Vitamin K.
Q: What are anomers? A: Isomers that differ in configuration only at the hemiacetal/hemiketal carbon (e.g., α-D-glucose and β-D-glucose).