Your progress 0 /35 answered
· 0 correct
(0 %)
Set complete — review the explanations below, then reset and run it again for retention.
Q1 of 35
The volume occupied by 2 moles of an ideal gas at STP is: A 11.2 L B 22.4 L C 33.6 L D 44.8 L
Correct Answer: Option D — 44.8 L Detailed Academic Explanation: At STP, 1 mole occupies 22.4 L. Therefore, 2 moles occupy 44.8 L.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q2 of 35
According to Avogadro's law, equal volumes of gases at same temperature and pressure contain equal numbers of: A Atoms B Molecules C Electrons D Protons
Correct Answer: Option B — Molecules Detailed Academic Explanation: Avogadro's law states that V ∝ n (number of moles) at constant T and P, meaning equal volumes contain equal number of molecules.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q3 of 35
Which of the following is NOT an assumption of kinetic molecular theory of gases? A Gas molecules have negligible volume B Gas molecules exert attractive forces on each other C Collisions between molecules are perfectly elastic D Molecules move in random straight-line motion
Correct Answer: Option B — Gas molecules exert attractive forces on each other Detailed Academic Explanation: Ideal gas molecules are assumed to have no intermolecular forces. Real gases deviate due to attractive forces especially at high pressure/low temperature.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q4 of 35
Graham's law of diffusion states that the rate of diffusion of a gas is inversely proportional to the square root of its: A Volume B Pressure C Density D Temperature
Correct Answer: Option C — Density Detailed Academic Explanation: Rate ∝ 1/√d (at constant T and P) or rate ∝ 1/√M, where d = density and M = molar mass.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q5 of 35
The temperature at which a real gas obeys ideal gas law over an appreciable range of pressure is called: A Critical temperature B Boyle temperature C Inversion temperature D Absolute zero
Correct Answer: Option B — Boyle temperature Detailed Academic Explanation: At Boyle temperature, the effects of molecular volume and intermolecular forces cancel, making Z ≈ 1 over a range of pressures.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q6 of 35
Raoult's law applies to: A All solutions B Ideal solutions only C Non-ideal solutions only D Electrolyte solutions only
Correct Answer: Option B — Ideal solutions only Detailed Academic Explanation: Raoult's law (P_A = X_A·P°_A) holds for ideal solutions where intermolecular forces A-A ≈ B-B ≈ A-B.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q7 of 35
The colligative property that depends only on number of solute particles is: A Vapor pressure lowering B Boiling point elevation C Freezing point depression D All of the above
Correct Answer: Option D — All of the above Detailed Academic Explanation: All colligative properties depend solely on solute particle concentration, not on their identity.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q8 of 35
The van't Hoff factor i for NaCl is approximately: A 1 B 2 C 3 D 4
Correct Answer: Option B — 2 Detailed Academic Explanation: NaCl dissociates into 2 ions (Na⁺ and Cl⁻), so i ≈ 2 in dilute solutions.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q9 of 35
A solution with pH = 3 has hydrogen ion concentration of: A 10⁻³ M B 10⁻⁷ M C 10⁻¹¹ M D 3 M
Correct Answer: Option A — 10⁻³ M Detailed Academic Explanation: pH = -log[H⁺] ⇒ [H⁺] = 10^(-pH) = 10⁻³ M.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q10 of 35
The pH of 0.01 M HCl solution is: A 1 B 2 C 3 D 4
Correct Answer: Option B — 2 Detailed Academic Explanation: HCl is strong acid, completely dissociated: [H⁺] = 0.01 M = 10⁻² M ⇒ pH = 2.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q11 of 35
Which of the following is a buffer solution? A HCl + NaCl B CH₃COOH + CH₃COONa C H₂SO₄ + Na₂SO₄ D NaOH + NaCl
Correct Answer: Option B — CH₃COOH + CH₃COONa Detailed Academic Explanation: Buffer contains weak acid and its conjugate base (or weak base and conjugate acid). CH₃COOH/CH₃COO⁻ resists pH change.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q12 of 35
The hydrolysis of sodium acetate (CH₃COONa) produces a solution that is: A Acidic B Basic C Neutral D Amphoteric
Correct Answer: Option B — Basic Detailed Academic Explanation: CH₃COO⁻ + H₂O ⇌ CH₃COOH + OH⁻. Acetate ion (conjugate base of weak acid) hydrolyzes to produce OH⁻, making solution basic.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q13 of 35
According to Le Chatelier's principle, increasing pressure on N₂ + 3H₂ ⇌ 2NH₃ will: A Shift equilibrium left B Shift equilibrium right C No effect D Decrease rate
Correct Answer: Option B — Shift equilibrium right Detailed Academic Explanation: Increasing pressure favors side with fewer gas moles. Left: 4 moles gas; right: 2 moles gas. Equilibrium shifts right to produce more NH₃.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q14 of 35
The equilibrium constant K_c for a reaction depends on: A Concentration of reactants B Concentration of products C Temperature D Catalyst
Correct Answer: Option C — Temperature Detailed Academic Explanation: K_c depends only on temperature. Catalyst affects rate but not equilibrium position.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q15 of 35
For the reaction 2SO₂ + O₂ ⇌ 2SO₃, the relationship between K_p and K_c is: A K_p = K_c B K_p = K_c(RT) C K_p = K_c(RT)⁻¹ D K_p = K_c(RT)²
Correct Answer: Option C — K_p = K_c(RT)⁻¹ Detailed Academic Explanation: Δn = moles gaseous products - moles gaseous reactants = 2 - 3 = -1. K_p = K_c(RT)^Δn = K_c(RT)⁻¹.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q16 of 35
The half-life of a first-order reaction: A Depends on initial concentration B Is independent of initial concentration C Increases with concentration D Decreases with concentration
Correct Answer: Option B — Is independent of initial concentration Detailed Academic Explanation: For first-order: t_{1/2} = 0.693/k, independent of initial concentration.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q17 of 35
The first law of thermodynamics is a statement of conservation of: A Mass B Energy C Momentum D Charge
Correct Answer: Option B — Energy Detailed Academic Explanation: ΔU = q + w: change in internal energy equals heat added to system plus work done on system (energy conservation).
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q18 of 35
The enthalpy change for an exothermic reaction is: A Positive B Negative C Zero D Undefined
Correct Answer: Option B — Negative Detailed Academic Explanation: Exothermic: heat released by system to surroundings ⇒ ΔH < 0 (negative).
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q19 of 35
Hess's law states that the enthalpy change of a reaction depends only on: A Path taken B Initial and final states C Rate of reaction D Catalyst used
Correct Answer: Option B — Initial and final states Detailed Academic Explanation: Enthalpy is a state function; ΔH depends only on initial and final states, not on path taken.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q20 of 35
The standard enthalpy of formation of an element in its most stable form is: A Positive B Negative C Zero D Variable
Correct Answer: Option C — Zero Detailed Academic Explanation: By definition, ΔH_f° = 0 for elements in their standard states (e.g., O₂(g), C(graphite), Na(s)).
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q21 of 35
The entropy of a perfectly crystalline substance at absolute zero is: A Maximum B Minimum C Zero D Undefined
Correct Answer: Option C — Zero Detailed Academic Explanation: Third law of thermodynamics: S → 0 as T → 0 K for perfect crystal.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q22 of 35
The relationship between ΔG° and equilibrium constant K is: A ΔG° = RT ln K B ΔG° = -RT ln K C ΔG° = -RT/K D ΔG° = RT/K
Correct Answer: Option B — ΔG° = -RT ln K Detailed Academic Explanation: ΔG° = -RT ln K. When K > 1, ΔG° < 0 (spontaneous as written).
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q23 of 35
The compound used as antiseptic and in borax bead test is: A Boric acid B Borax C Diborane D Boron nitride
Correct Answer: Option B — Borax Detailed Academic Explanation: Borax (Na₂B₄O₇·10H₂O) solution is mild antiseptic; also used in borax bead test for metal ions.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q24 of 35
Fehling's solution gives red precipitate with: A Aromatic aldehydes B Aliphatic aldehydes C Ketones D Alcohols
Correct Answer: Option B — Aliphatic aldehydes Detailed Academic Explanation: Fehling's solution (Cu²⁺ tartrate complex) oxidized by aliphatic aldehydes to give red Cu₂O precipitate; aromatic aldehydes and ketones do not react.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q25 of 35
Photochemical smog contains high concentration of: A SO₂ B CO C O₃ D NO
Correct Answer: Option C — O₃ Detailed Academic Explanation: Photochemical smog forms when NOₓ and hydrocarbons react in sunlight producing ozone (O₃), PAN, and other oxidants.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q26 of 35
The pH of normal rainwater is approximately: A 5.6 B 7.0 C 8.2 D 4.0
Correct Answer: Option A — 5.6 Detailed Academic Explanation: Normal rainwater has pH ~5.6 due to dissolution of atmospheric CO₂ forming carbonic acid: CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q27 of 35
The number of moles in 11.2 L of O₂ gas at STP is: A 0.5 B 1.0 C 1.5 D 2.0
Correct Answer: Option A — 0.5 Detailed Academic Explanation: At STP, 22.4 L = 1 mole. Therefore, 11.2 L = 0.5 mole.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q28 of 35
The molarity of solution containing 4 g NaOH in 250 mL solution is: A 0.25 M B 0.4 M C 0.5 M D 1.0 M
Correct Answer: Option B — 0.4 M Detailed Academic Explanation: Moles of NaOH = 4/40 = 0.1 mol. Volume = 0.25 L. Molarity = 0.1/0.25 = 0.4 M.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q29 of 35
The molality of solution containing 5.85 g NaCl in 500 g water is: A 0.1 m B 0.2 m C 0.5 m D 1.0 m
Correct Answer: Option B — 0.2 m Detailed Academic Explanation: Moles of NaCl = 5.85/58.5 = 0.1 mol. Mass of solvent = 0.5 kg. Molality = 0.1/0.5 = 0.2 m.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q30 of 35
Which concentration term is temperature independent? A Molarity B Molality C Normality D Volume percent
Correct Answer: Option B — Molality Detailed Academic Explanation: Molality (moles/kg solvent) depends on mass, not volume, so unaffected by temperature changes.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q31 of 35
The equivalent weight of KMnO₄ in acidic medium is: A M/2 B M/3 C M/5 D M
Correct Answer: Option C — M/5 Detailed Academic Explanation: In acidic medium: MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O. n-factor = 5 ⇒ Eq. wt. = M/5.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q32 of 35
Which is strongest reducing agent? A Li B Na C K D Rb
Correct Answer: Option A — Li Detailed Academic Explanation: Lithium has most negative electrode potential (E° = -3.04 V) despite lower reactivity in water due to kinetic factors; thermodynamically strongest reducing agent.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q33 of 35
The compound used as antiseptic is: A Phenol B Ethanol C Both A and B D Neither A nor B
Correct Answer: Option C — Both A and B Detailed Academic Explanation: Dilute phenol solution (carbolic acid) and 70% ethanol both have antiseptic properties.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q34 of 35
The reagent used to distinguish between primary, secondary and tertiary alcohols is: A Tollens' reagent B Fehling's solution C Lucas reagent D Iodoform reagent
Correct Answer: Option C — Lucas reagent Detailed Academic Explanation: Lucas test based on rate of formation of alkyl chlorides (turbidity) distinguishes 1°, 2°, 3° alcohols.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry
Q35 of 35
The compound that is major greenhouse gas is: A Carbon dioxide B Methane C Nitrous oxide D Water vapor
Correct Answer: Option A — Carbon dioxide Detailed Academic Explanation: CO₂ contributes ~60% of enhanced greenhouse effect from human activities; water vapor is most abundant but concentration controlled by temperature.
💡 Key Conceptual Anchor:
Physical Chemistry & Stoichiometry