PYQ-Based with Exam Year | Polytechnic | State Board | Semester 1 & 2
1. The mass of one mole of electrons is approximately:
a) 1 g
b) 0.55 mg
c) 9.1 × 10⁻³¹ g
d) 6.022 × 10²³ g
View Answer
b) 0.55 mg
Explanation: Mass of 1 electron = 9.1 × 10⁻³¹ kg = 9.1 × 10⁻²⁸ g → 1 mol = 6.022 × 10²³ × 9.1 × 10⁻²⁸ ≈ 5.5 × 10⁻⁴ g = 0.55 mg.
2. The number of atoms in 12 g of carbon-12 is:
a) 1
b) 12
c) 6.022 × 10²³
d) 12 × 6.022 × 10²³
View Answer
c) 6.022 × 10²³
Explanation: By definition, 12 g of C-12 contains 1 mole = Nₐ atoms.
3. The empirical formula of a compound with 40% C, 6.67% H, 53.33% O is:
a) CH₂O
b) C₂H₄O₂
c) CH₄O
d) C₃H₆O₃
View Answer
a) CH₂O
Explanation: C:H:O = 40/12 : 6.67/1 : 53.33/16 = 3.33:6.67:3.33 → divide by 3.33 → 1:2:1 → CH₂O.
4. The volume of oxygen required to burn 1 L of methane completely is:
a) 1 L
b) 2 L
c) 3 L
d) 4 L
View Answer
b) 2 L
Explanation: CH₄ + 2O₂ → CO₂ + 2H₂O → 1 vol CH₄ : 2 vol O₂ (Gay-Lussac’s law).
5. The root mean square velocity of a gas is proportional to:
a) T
b) √T
c) T²
d) 1/√T
View Answer
b) √T
Explanation: u_rms = √(3RT/M) ∝ √T.
6. The unit of rate constant for a zero-order reaction is:
a) s⁻¹
b) mol L⁻¹ s⁻¹
c) L mol⁻¹ s⁻¹
d) mol² L⁻² s⁻¹
View Answer
b) mol L⁻¹ s⁻¹
Explanation: Rate = k [A]⁰ → k = rate = mol L⁻¹ s⁻¹.
7. The half-life of a first-order reaction is:
a) Dependent on initial concentration
b) Independent of initial concentration
c) Proportional to concentration
d) Inversely proportional to k
View Answer
b) Independent of initial concentration
Explanation: t₁/₂ = 0.693 / k.
8. The activation energy is the energy required to:
a) Start a reaction
b) Form products
c) Reach transition state
d) Break bonds only
View Answer
c) Reach transition state
Explanation: Eₐ = energy of transition state – energy of reactants.
9. The catalyst lowers the activation energy by:
a) Providing alternate path
b) Increasing temperature
c) Changing ΔH
d) Increasing concentration
View Answer
a) Providing alternate path
Explanation: New mechanism with lower Eₐ.
10. The order of reaction can be determined from:
a) Rate law expression
b) Stoichiometry
c) Molecularity
d) Equilibrium constant
View Answer
a) Rate law expression
Explanation: Experimentally determined from rate vs concentration data.
11. The conjugate acid of NH₃ is:
a) NH₂⁻
b) NH₄⁺
c) N₂
d) HNO₃
View Answer
b) NH₄⁺
Explanation: NH₃ + H⁺ → NH₄⁺.
12. The pH of 10⁻⁸ M HCl is approximately:
a) 8
b) 7
c) 6.96
d) 6
View Answer
c) 6.96
Explanation: [H⁺] from HCl = 10⁻⁸ M, from water = 10⁻⁷ M → total ≈ 1.1 × 10⁻⁷ → pH = 6.96.
13. The buffer solution resists change in pH due to:
a) Common ion effect
b) Le Chatelier’s principle
c) Both a and b
d) None
View Answer
c) Both a and b
Explanation: Weak acid/base + salt → equilibrium shift on adding H⁺/OH⁻.
14. The end point in acid-base titration is detected by:
a) Change in color of indicator
b) Change in temperature
c) Precipitation
d) Evolution of gas
View Answer
a) Change in color of indicator
Explanation: Indicator changes color at equivalence point.
15. The normality of 49 g/L H₂SO₄ (M = 98) is:
a) 0.5 N
b) 1 N
c) 2 N
d) 0.1 N
View Answer
b) 1 N
Explanation: M = 49/98 = 0.5 M → N = M × 2 = 1 N.
16. The hybridization in CO₂ is:
a) sp
b) sp²
c) sp³
d) dsp²
View Answer
a) sp
Explanation: Linear → sp hybridization (2σ + 2π bonds).
17. The bond order in O₂ molecule is:
a) 1
b) 2
c) 3
d) 1.5
View Answer
b) 2
Explanation: (σ2s)²(σ*2s)²(σ2p)²(π2p)⁴(π*2p)² → BO = (8–4)/2 = 2.
18. The dipole moment of CO₂ is:
a) Zero
b) High
c) Moderate
d) Negative
View Answer
a) Zero
Explanation: Linear symmetrical → vector sum of dipoles = 0.
19. The VSEPR theory predicts the shape of:
a) SF₆ → Octahedral
b) NH₃ → Tetrahedral
c) H₂O → Linear
d) CO₂ → Bent
View Answer
a) SF₆ → Octahedral
Explanation: 6 bond pairs → octahedral.
20. The strongest van der Waals force is:
a) London dispersion
b) Dipole-dipole
c) Dipole-induced dipole
d) Ion-dipole
View Answer
d) Ion-dipole
Explanation: Strongest among intermolecular forces.
21. The ore of iron is:
a) Bauxite
b) Hematite
c) Galena
d) Malachite
View Answer
b) Hematite
Explanation: Fe₂O₃.
22. The chemical used for etching glass is:
a) HCl
b) HNO₃
c) HF
d) H₂SO₄
View Answer
c) HF
Explanation: SiO₂ + 4HF → SiF₄ + 2H₂O.
23. The monomer of Bakelite is:
a) Phenol + Formaldehyde
b) Urea + Formaldehyde
c) Melamine + Formaldehyde
d) Ethylene glycol + Terephthalic acid
View Answer
a) Phenol + Formaldehyde
Explanation: Thermosetting polymer.
24. The functional group in ketone is:
a) –OH
b) –CHO
c) >C=O
d) –COOH
View Answer
c) >C=O
Explanation: Carbonyl group with two alkyl groups.
25. The IUPAC name of CH₃COCH₃ is:
a) Propanone
b) Propanal
c) Propanol
d) Ethyl methyl ketone
View Answer
a) Propanone
Explanation: 3-carbon chain with keto group at C-2.
26. The number of isomeric alkanes with formula C₅H₁₂ is:
a) 2
b) 3
c) 4
d) 5
View Answer
b) 3
Explanation: n-pentane, isopentane, neopentane.
27. The reagent used to convert alcohol to aldehyde is:
a) KMnO₄
b) PCC
c) LiAlH₄
d) NaBH₄
View Answer
b) PCC
Explanation: Pyridinium chlorochromate stops at aldehyde.
28. The test for unsaturation is:
a) Fehling’s test
b) Bromine water test
c) Tollen’s test
d) Iodoform test
View Answer
b) Bromine water test
Explanation: Decolorization indicates C=C or C≡C.
29. The polymer used for non-stick coating is:
a) PVC
b) PTFE
c) PE
d) PP
View Answer
b) PTFE
Explanation: Polytetrafluoroethylene (Teflon).
30. The chemical formula of bleaching powder is:
a) CaOCl₂
b) Ca(OCl)₂
c) NaOCl
d) Cl₂
View Answer
a) CaOCl₂
Explanation: Calcium chlorohypochlorite.
31. The gas evolved when Zn reacts with dil. H₂SO₄ is:
a) O₂
b) H₂
c) SO₂
d) CO₂
View Answer
b) H₂
Explanation: Zn + H₂SO₄ → ZnSO₄ + H₂↑.
32. The catalyst used in Haber’s process is:
a) V₂O₅
b) Fe
c) Ni
d) Pt
View Answer
b) Fe
Explanation: N₂ + 3H₂ → 2NH₃ (Fe + Mo promoter).
33. The chemical name of laughing gas is:
a) NO
b) N₂O
c) NO₂
d) NH₃
View Answer
b) N₂O
Explanation: Nitrous oxide.
34. The allotrope of carbon used as moderator in nuclear reactor is:
a) Diamond
b) Graphite
c) Fullerene
d) Charcoal
View Answer
b) Graphite
Explanation: Slows down neutrons.
35. The hybridization in graphite is:
a) sp
b) sp²
c) sp³
d) sp³d
View Answer
b) sp²
Explanation: Trigonal planar, layered structure.
36. The monomer of nylon-6,6 is:
a) Caprolactam
b) Adipic acid + Hexamethylenediamine
c) Ethylene glycol
d) Terephthalic acid
View Answer
b) Adipic acid + Hexamethylenediamine
Explanation: Condensation polymerization.
37. The test for carboxylic acid is:
a) NaHCO₃ test (CO₂ evolution)
b) Fehling’s test
c) Iodoform test
d) Bromine water
View Answer
a) NaHCO₃ test (CO₂ evolution)
Explanation: RCOOH + NaHCO₃ → RCOONa + CO₂ + H₂O.
38. The functional group in ester is:
a) –COOH
b) –CHO
c) –COOR
d) –NH₂
View Answer
c) –COOR
Explanation: Carboxylate group.
39. The chemical formula of chloroform is:
a) CHCl₃
b) CCl₄
c) CH₂Cl₂
d) CH₃Cl
View Answer
a) CHCl₃
Explanation: Trichloromethane.
40. The reagent used in Friedel-Crafts acylation is:
a) AlCl₃
b) FeCl₃
c) ZnCl₂
d) SnCl₄
View Answer
a) AlCl₃
Explanation: Lewis acid catalyst for RCOCl + ArH.
41. The catalyst used in Ostwald’s process is:
a) Fe
b) Pt
c) V₂O₅
d) Ni
View Answer
b) Pt
Explanation: 4NH₃ + 5O₂ → 4NO + 6H₂O (Pt gauge).
42. The chemical name of oil of vitriol is:
a) HCl
b) HNO₃
c) H₂SO₄
d) H₃PO₄
View Answer
c) H₂SO₄
Explanation: Concentrated sulfuric acid.
43. The number of water molecules in gypsum is:
a) 0
b) ½
c) 2
d) 5
View Answer
c) 2
Explanation: CaSO₄·2H₂O.
44. The gas responsible for Bhopal tragedy was:
a) CO
b) SO₂
c) MIC
d) Cl₂
View Answer
c) MIC
Explanation: Methyl isocyanate (1984).
45. The polymer used in optical lenses is:
a) PMMA
b) PVC
c) PS
d) LDPE
View Answer
a) PMMA
Explanation: Polymethyl methacrylate (acrylic).
46. The test for aldehyde (not ketone) is:
a) 2,4-DNP test
b) Tollen’s test
c) Iodoform test
d) Fehling’s test
View Answer
b) Tollen’s test
Explanation: Silver mirror test (only aldehydes).
47. The IUPAC name of (CH₃)₂CHOH is:
a) Propan-1-ol
b) Propan-2-ol
c) 2-Methylpropan-2-ol
d) Ethanol
View Answer
b) Propan-2-ol
Explanation: OH on middle carbon of 3-carbon chain.
48. The monomer of polystyrene is:
a) Ethylene
b) Styrene
c) Vinyl chloride
d) Acrylonitrile
View Answer
b) Styrene
Explanation: C₆H₅CH=CH₂.
49. The chemical used as refrigerant is:
a) CCl₄
b) CHCl₃
c) Freon (CCl₂F₂)
d) CH₄
View Answer
c) Freon (CCl₂F₂)
Explanation: Dichlorodifluoromethane.
50. The number of π bonds in benzene is:
a) 3
b) 6
c) 9
d) 12
View Answer
a) 3
Explanation: 3 alternating double bonds → 3 σ + 3 π bonds between carbons.
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