Q.1 Which of the following is the lightest alkali metal?
Lithium
Sodium
Potassium
Rubidium
Explanation - Lithium is the first element of the alkali metal group with the lowest atomic mass (6.94).
Correct answer is: Lithium
Q.2 Which gas is released when zinc reacts with hydrochloric acid?
Oxygen
Hydrogen
Nitrogen
Chlorine
Explanation - Zinc + HCl → ZnCl₂ + H₂, hence hydrogen gas is evolved.
Correct answer is: Hydrogen
Q.3 What is the oxidation state of sulfur in H₂SO₄?
+2
+4
+6
+8
Explanation - Sulfur in H₂SO₄ has an oxidation number of +6 after balancing charges.
Correct answer is: +6
Q.4 Which element is known as 'King of Chemicals' due to its wide industrial use?
H₂SO₄
NaOH
HNO₃
HCl
Explanation - Sulfuric acid is called the King of Chemicals due to its large-scale applications in industries.
Correct answer is: H₂SO₄
Q.5 Which of the following is a noble gas?
Oxygen
Chlorine
Argon
Nitrogen
Explanation - Noble gases include He, Ne, Ar, Kr, Xe, Rn, known for inertness.
Correct answer is: Argon
Q.6 Which oxide of nitrogen is called 'laughing gas'?
NO
NO₂
N₂O
N₂O₅
Explanation - Nitrous oxide (N₂O) is also known as laughing gas due to its anesthetic effect.
Correct answer is: N₂O
Q.7 Which element has the highest electronegativity?
Oxygen
Nitrogen
Fluorine
Chlorine
Explanation - Fluorine has the highest electronegativity value (3.98 on the Pauling scale).
Correct answer is: Fluorine
Q.8 Which halogen is a liquid at room temperature?
Fluorine
Chlorine
Bromine
Iodine
Explanation - Bromine is unique among halogens as it exists as a reddish-brown liquid at room temperature.
Correct answer is: Bromine
Q.9 Which of the following elements is not a transition metal?
Fe
Cu
Zn
Ni
Explanation - Zinc has a completely filled d-orbital (3d¹⁰) and hence is not considered a transition metal.
Correct answer is: Zn
Q.10 The brown ring test is used to detect the presence of which ion?
Nitrate
Chloride
Sulfate
Carbonate
Explanation - The brown ring test confirms the presence of nitrate ions using FeSO₄ and concentrated H₂SO₄.
Correct answer is: Nitrate
Q.11 Which of the following compounds is used in the preparation of plaster of Paris?
CaSO₄·2H₂O
CaSO₄·½H₂O
CaCO₃
Ca(OH)₂
Explanation - Plaster of Paris is chemically CaSO₄·½H₂O (calcium sulfate hemihydrate).
Correct answer is: CaSO₄·½H₂O
Q.12 Which element is used in the galvanization of iron?
Zinc
Copper
Silver
Tin
Explanation - Galvanization is the process of coating iron with a layer of zinc to prevent rusting.
Correct answer is: Zinc
Q.13 Which gas is known as 'Marsh gas'?
Methane
Ethane
Propane
Butane
Explanation - Methane is called marsh gas as it is formed by decomposition of organic matter in marshy areas.
Correct answer is: Methane
Q.14 Which alkali metal is stored in kerosene?
Calcium
Sodium
Magnesium
Barium
Explanation - Sodium is stored under kerosene because it reacts vigorously with air and moisture.
Correct answer is: Sodium
Q.15 Which acid is called 'aqua fortis'?
HCl
HNO₃
H₂SO₄
H₃PO₄
Explanation - Nitric acid (HNO₃) is traditionally known as aqua fortis.
Correct answer is: HNO₃
Q.16 Which of the following oxides is amphoteric?
Na₂O
CaO
Al₂O₃
CO₂
Explanation - Aluminium oxide is amphoteric, reacting with both acids and bases.
Correct answer is: Al₂O₃
Q.17 Which of the following metals is used in making light filaments?
Copper
Silver
Tungsten
Aluminium
Explanation - Tungsten has a very high melting point, making it suitable for lamp filaments.
Correct answer is: Tungsten
Q.18 What is the formula of bleaching powder?
CaCl₂
Ca(OH)₂
CaOCl₂
CaCO₃
Explanation - Bleaching powder is chemically calcium oxychloride, CaOCl₂.
Correct answer is: CaOCl₂
Q.19 Which element is used in the manufacture of semiconductors?
Iron
Silicon
Magnesium
Copper
Explanation - Silicon is widely used in the electronics industry for making semiconductors.
Correct answer is: Silicon
Q.20 Which of the following ions imparts a brick-red flame color?
Sodium
Calcium
Barium
Potassium
Explanation - Calcium imparts a characteristic brick-red color in flame tests.
Correct answer is: Calcium
Q.21 Which of the following is used as a drying agent?
NaCl
CaCl₂
KCl
MgCl₂
Explanation - Anhydrous calcium chloride is commonly used as a drying agent due to its hygroscopic nature.
Correct answer is: CaCl₂
Q.22 Which of the following is not a greenhouse gas?
CO₂
CH₄
O₂
N₂O
Explanation - Oxygen is not a greenhouse gas; CO₂, CH₄, and N₂O trap heat in the atmosphere.
Correct answer is: O₂
Q.23 Which of the following is the ore of aluminium?
Bauxite
Galena
Hematite
Magnetite
Explanation - Bauxite (Al₂O₃·2H₂O) is the chief ore of aluminium.
Correct answer is: Bauxite
Q.24 Which allotrope of carbon is used as a lubricant?
Diamond
Graphite
Fullerene
Charcoal
Explanation - Graphite has layers of carbon atoms with weak forces between them, allowing it to act as a lubricant.
Correct answer is: Graphite
Q.25 Which acid is present in vinegar?
Acetic acid
Formic acid
Oxalic acid
Citric acid
Explanation - Vinegar contains about 4–8% acetic acid (CH₃COOH).
Correct answer is: Acetic acid