JST Chemistry MCQs – STS Pattern
Section A – Organic Chemistry
1. Methane (CH₄) is classified as:
Answer: Alkane – Methane has only single bonds between carbon and hydrogen.
2. Ethanol can be prepared by:
Answer: Fermentation of sugar – Yeast converts sugar into ethanol.
3. Functional group in alcohols is:
Answer: –OH – Hydroxyl group defines alcohols.
4. Acetylene is:
Answer: C₂H₂ – It is an alkyne with a triple bond.
5. Sugar is a:
Answer: Carbohydrate – Sugars are energy-providing carbs.
6. Methanol is commonly known as:
Answer: Wood alcohol – Produced from wood distillation.
7. Functional group in aldehydes is:
Answer: –CHO – Characteristic aldehyde group.
8. Benzene is classified as:
Answer: Aromatic – Benzene has a ring structure with delocalized electrons.
9. Ethanoic acid is commonly called:
Answer: Vinegar – Common household acid.
10. Polymerization of ethene produces:
Answer: Polyethylene – Formed by addition polymerization.
11. Carboxylic acids contain the group:
Answer: –COOH – Defines organic acids.
12. Glucose formula:
Answer: C₆H₁₂O₆ – Monosaccharide sugar.
13. Amino acids are building blocks of:
Answer: Proteins – Proteins are made of amino acids.
14. Sucrose is:
Answer: Disaccharide – Composed of glucose + fructose.
Section B – Inorganic Chemistry
15. Atomic number of Oxygen is:
Answer: 8 – Number of protons in Oxygen atom.
16. Noble gases are chemically:
Answer: Inert – They have full outer electron shells.
17. Sodium reacts with water to form:
Answer: NaOH + H₂ – Sodium forms hydroxide and hydrogen gas.
18. Formula of washing soda is:
Answer: Na₂CO₃·10H₂O – Hydrated sodium carbonate.
19. Chemical symbol of Mercury:
Answer: Hg – Symbol comes from hydrargyrum.
20. Sodium is a:
Answer: Metal – Soft and highly reactive.
21. Group 1 elements are called:
Answer: Alkali metals – Highly reactive metals in first group.
22. Salt formed from reaction of acid and base is:
Answer: Neutralization – Reaction produces salt and water.
23. Chemical symbol for Iron:
Answer: Fe – From Latin “Ferrum”.
24. Water of crystallization in CuSO₄·5H₂O:
Answer: 5 molecules – Each formula unit binds 5 water molecules.
25. Hydrogen is obtained in lab by reaction of:
Answer: Zn + HCl – Displacement reaction produces H₂ gas.
26. Oxidation state of Oxygen in H₂O:
Answer: -2 – Standard oxidation state in compounds.
27. Atomic number defines:
Answer: Number of protons – Unique for each element.
28. Alkali metals stored in:
Answer: Kerosene – Prevents reaction with air/moisture.
29. Halogens are in group:
Answer: 17 – Fluorine, chlorine, bromine, iodine, astatine.
30. Hydrogen chloride gas dissolves in water to form:
Answer: Hydrochloric acid – Strong acid formation.
31. Common name of NaHCO₃:
Answer: Baking soda – Used in cooking and cleaning.
32. Sulfuric acid is:
Answer: Strong acid – Highly corrosive and concentrated.
33. Chlorine is:
Answer: Green gas – Toxic and reactive halogen.
34. Group 0 elements are:
Answer: Noble gases – Inert due to full outer shell.
35. Oxides of metals are usually:
Answer: Basic – React with acids to form salt and water.
36. Oxides of non-metals are usually:
Answer: Acidic – Example: CO₂, SO₂.
37. Ammonia formula:
Answer: NH₃ – Weak base, pungent gas.
38. Boiling point of water at 1 atm:
Answer: 100°C – Standard boiling point.
39. Rusting of iron requires:
Answer: Oxygen + Water – Causes Fe₂O₃·xH₂O formation.
40. Acid that reacts with metals to produce hydrogen:
Answer: Hydrochloric acid – Common displacement reaction.
41. Alkali metals form:
Answer: Hydroxides – Very soluble and strong base.
42. Electrolysis of water gives:
Answer: Hydrogen + Oxygen – Decomposition reaction.
43. White precipitate forms with BaCl₂ + H₂SO₄:
Answer: BaSO₄ – Insoluble sulfate.
44. Gas produced in photosynthesis:
Answer: Oxygen – Plants release O₂ during photosynthesis.
45. Base soluble in water is called:
Answer: Alkali – Dissolves in water to give OH⁻ ions.
46. Negative electrode in electrolysis is:
Answer: Cathode – Electrons flow towards cathode.
47. Positive electrode in electrolysis is:
Answer: Anode – Electrons leave at anode.
48. Breaking compound into simpler substance is called:
Answer: Decomposition – Single compound splits into simpler substances.
49. Attraction between atoms or ions is called:
Answer: Chemical bond – Forces holding atoms together.
50. The atomic number of an element represents:
Answer: B) Number of protons
51. The mass number is the sum of:
Answer: C) Protons and neutrons
52. Isotopes have:
Answer: B) Same atomic number
53. Example of isotope:
Answer: A) Carbon-12 and Carbon-14
54. Valency of Sodium is:
Answer: C) 1
55. Valency of Oxygen is:
Answer: B) 2
56. Valency of Nitrogen is:
Answer: C) 3
57. Sodium belongs to group:
Answer: A) Group 1
58. Chlorine belongs to group:
Answer: C) 17
59. Noble gases are present in group:
Answer: C) 18
60. Helium is a:
Answer: C) Noble gas
61. Periodic table is arranged according to:
Answer: B) Atomic number
62. Horizontal rows in periodic table are called:
Answer: B) Periods
63. Vertical columns are called:
Answer: B) Groups
64. Metals are good conductors of:
Answer: A) Heat and electricity
65. Non-metals are:
Answer: B) Insulators
66. Iron is a:
Answer: B) Metal
67. Sulfur is a:
Answer: B) Non-metal
68. Silicon is a:
Answer: C) Metalloid
69. Water formula is:
Answer: A) H₂O
70. Carbon dioxide formula:
Answer: B) CO₂
71. Ammonia formula:
Answer: A) NH₃
72. Methane formula:
Answer: A) CH₄
73. Hydrochloric acid formula:
Answer: A) HCl
74. Sulfuric acid formula:
Answer: B) H₂SO₄
75. Nitric acid formula:
Answer: C) HNO₃
76. Acetic acid formula is:
Answer: A) CH₃COOH
77. Baking soda formula is:
Answer: B) NaHCO₃
78. Washing soda formula is:
Answer: A) Na₂CO₃·10H₂O
79. Common salt formula is:
Answer: B) NaCl
80. Quick lime is:
Answer: B) CaO
81. Slaked lime is:
Answer: C) Ca(OH)₂
82. Plaster of Paris formula:
Answer: A) CaSO₄·½H₂O
83. Gypsum formula:
Answer: A) CaSO₄·2H₂O
84. Acid turns blue litmus into:
Answer: A) Red
85. Base turns red litmus into:
Answer: A) Blue
86. pH value of acid is:
Answer: A) Less than 7
87. pH value of base is:
Answer: C) More than 7
88. Neutral solution pH is:
Answer: C) 7
89. Example of acid:
Answer: A) HCl
90. Example of base:
Answer: B) NaOH
91. Neutralization reaction forms:
Answer: C) Salt and water
92. Example of neutralization:
Answer: A) HCl + NaOH
93. Electrolysis means:
Answer: C) Chemical decomposition by electricity
94. Electrolyte conducts electricity in:
Answer: B) Liquid state
95. Anode is:
Answer: A) Positive electrode
96. Cathode is:
Answer: B) Negative electrode
97. Oxidation is:
Answer: A) Loss of electrons
98. Reduction is:
Answer: B) Gain of electrons
99. Rusting is example of:
Answer: B) Oxidation
100. Rust is formed on:
Answer: B) Iron
101. Rusting requires:
Answer: C) Oxygen and water
102. Stainless steel contains:
Answer: B) Iron and chromium
103. Alloy is a mixture of:
Answer: A) Metal and metal or non-metal
104. Brass is an alloy of:
Answer: A) Copper and zinc
105. Bronze is an alloy of:
Answer: A) Copper and tin
106. Steel is an alloy of:
Answer: A) Iron and carbon
107. Galvanization protects iron from:
Answer: B) Rusting
108. Galvanization is coating of iron with:
Answer: B) Zinc
109. Electroplating is done by:
Answer: C) Electrolysis
110. Example of electroplating:
Answer: A) Gold plating on jewelry
111. Petroleum is a:
Answer: B) Liquid fuel
112. Natural gas is mainly:
Answer: A) Methane
113. LPG stands for:
Answer: A) Liquid Petroleum Gas
114. CNG stands for:
Answer: A) Compressed Natural Gas
115. Fossil fuels are:
Answer: B) Non-renewable
116. Coal is used as:
Answer: A) Fuel
117. Coke is obtained from:
Answer: A) Coal
118. Coal tar is used in:
Answer: A) Roads and chemicals
119. Fractional distillation is used in:
Answer: A) Petroleum refining
120. Petrol is obtained from:
Answer: B) Petroleum
121. Diesel is obtained from:
Answer: A) Petroleum
122. Kerosene oil is used in:
Answer: A) Lamps and stoves
123. Paraffin wax is used in:
Answer: A) Candles
124. Chemical reaction produces:
Answer: A) New substance
125. Burning of fuel is:
Answer: A) Chemical reaction