Lucid Mind Lecture Notes - Solving MCQs Paper 1 Variant 2 (March 2020)

Introduction

• Presenter: Majid
• Topic: Solving multiple choice questions from Paper 1, Variant 2, March 2020.
• Purpose: To guide through solving the questions.

Question 1: Protons, Neutrons, and Electrons in Fe+3 Ion

• Atomic number of Fe: 26
• Mass number: 54
• Protons: 26
• Electrons: 23 (26 - 3 due to +3 charge)
• Neutrons: 28 (54 - 26)
• Answer: A

Question 2: Hydrocarbon Formulae

• Molecular vs Empirical Formula
• Butane: C4H10 (Empirical: C2H5)
• Ethane: C2H6 (Empirical: CH3)
• Pent-1-ene: C5H10 (Empirical: CH2)
• Propane: C3H8 (Empirical = Molecular)
• Answer: D (Propane)

Question 3: Bond Angles

• Ethane (C2H6): Tetrahedral, 109.8°
• CO2: Linear, 180°
• PF5: 120° & 90° angles
• SF6: All 90° angles
• Answer: A (Ethane)

Question 4: Enthalpy Change and Hess's Law

• Calculate decomposition using Hess's Law
• Equations involved:
  • 2 NaHCO3 → Na2CO3 + H2O + CO2
  • NaHCO3 + HCl → NaCl + H2O + CO2
  • Na2CO3 + 2 HCl → 2 NaCl + H2O + CO2
• Enthalpy Change (B): 8.65 kJ/mol
• Answer: C

Question 5: Oxidation States

• Oxidation state calculation for V and S
• VO2+ to V+3: V = +5 to +3
• SO2 to SO4^2-: S = +4 to +6
• Answer: D

Question 6: Units of Kc

• Reaction: AgCl + 2NH3 → [Ag(NH3)2]+ + Cl-
• AgCl is a solid, no concentration unit.
• Answer: A (No unit)

Question 7: Volume of Nitrogen from Decomposition

• NaN3 decomposes to N2
• Moles of NaN3: 2.307
• Volume: 83.05 dm³
• Answer: B

Question 8: Stable Ion Structure

• N5+ stability analyzed by octet rule
• Answer: C

Question 9: Volume Calculation Using Ideal Gas Law

• PV = nRT
• Find volume of container with 1.8g H2O at 500K, 200kPa
• Volume: 0.002 m³
• Answer: B

Question 10: Balancing Redox Equation

• Balancing charges and atoms
• For MnO4- and C2H4
• Answer: 6

Question 11: Equilibrium Yield Conditions (Contact Process)

• Catalyst: No change
• High pressure: Increases yield
• High temperature: Decreases yield
• Answer: B

Question 12: Oxides of Period 3 Elements

• X (P4O10) forms H3PO4
• Y (Na2O) neutralizes forming Na3PO4
• Answer: D

Question 13: Identification of Compound Z

• Soluble at low pH
• Answer: A (Barium Carbonate)

Question 14: NaOH and Cl2 Reaction

• Oxidation state changes
• Correct reactions described for cold aqueous sodium hydroxide
• Answer: C

Question 15: Ammonium Nitrate Reaction with Sodium Hydroxide

• Produces ammonia (turns red litmus blue)
• Answer: B

Question 16: Oxides of Period 3 Metals

• Sodium, Magnesium, Aluminium analysis
• Answer: D

Question 17: Decomposition of Calcium Nitrate

• Produces NO2 and O2, affecting litmus and flame brightness
• Answer: C

Question 18: Reaction of Sulfuric Acid with NaCl

• Acts as an acid only
• Answer: A

Question 19: Nitrogen and Compounds

• Haber process, reactivity, and compound formulae discussed
• Answer: C

Question 20: Functional Group Isomers

• Comparison of molecular formulas
• Answer: B

Question 21: Producing Butanenitrile

• Starting material and reagents
• Answer: B

Question 22: Reaction of Ethane Dioic Acid with Ethanol

• Formation of diester
• Answer: B

Question 23: Infrared Spectrum Analysis

• Identification of functional groups
• Answer: C

Question 24: Polymer Monomer Identification

• Finding the repeat units
• Answer: A

Question 25: Non-Cyclic Isomers

• Isomer count with formula C5H10
• Answer: D

Question 26: Reaction with HBr

• According to Markovnikov's rule
• Answer: C

Question 27: Propanoic Acid Production

• Reaction types and conditions
• Answer: A

Question 28: Lithium Aluminium Hydride Reduction

• Reduction of functional groups
• Answer: D

Question 29: Reflux with Dichromate

• Oxidation of alcohol to carboxylic acid
• Answer: B

Question 30: Description of Ester Groups

• Planarity and ester count
• Answer: D

Question 31: Properties of Carbon and Nitrogen

• Quantum number, bond formation
• Answer: C

Question 32: Properties Affected by Hydrogen Bonding

• Viscosity, boiling point, surface tension
• Answer: A

Question 33: Enthalpy Change Descriptions

• Formation, combustion, atomization
• Answer: D

Question 34: Rate of Reaction Influences

• Catalyst and concentration effects
• Answer: B

Question 35: Properties of Astatine

• Oxidizing power and thermal stability discussed
• Answer: D

Question 36: Dissolution of Metal Chlorides

• Acidic and neutral solutions
• Answer: B

Question 37: Mechanism Involving CN-

• Roles of CN- and reaction type
• Answer: A

Question 38: Yellow Precipitate Formation

• With alkaline aqueous iodine
• Answer: C

Question 39: Tetrafluoromethane Properties

• Decomposition, harm to ozone, polarity
• Answer: C

Question 40: Comparison of Ethene and Ethane

• Bond angles, reactivity, combustion gas volumes
• Answer: A

Conclusion

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