The valency of carbon is – (A) 2 (B) 4 (C) 1 (D) 3 Answer: (B)
Which of the following is a greenhouse gas? (A) CH₄ (B) CO₂ (C) N₂O (D) All of the above Answer: (D)
Water is a universal solvent because – (A) It is neutral (B) It has high boiling point (C) It dissolves many substances (D) It has high density Answer: (C)
The product formed when acid reacts with base is – (A) Salt (B) Water (C) Salt and water (D) Only gas Answer: (C)
Which is not a physical change? (A) Melting of ice (B) Boiling of water (C) Burning of wood (D) Breaking of glass Answer: (C)
Which gas is evolved on reaction of Zn with HCl? (A) Oxygen (B) Hydrogen (C) Carbon dioxide (D) Nitrogen Answer: (B)
The electrons in the outermost shell are called – (A) Core electrons (B) Valence electrons (C) Ionizing electrons (D) None of the above Answer: (B)
The most electronegative group in periodic table is – (A) Alkali metals (B) Halogens (C) Noble gases (D) Transition metals Answer: (B)
Chemical used in matchstick heads is – (A) Phosphorus (B) Potassium chlorate (C) Sulfur (D) All of the above Answer: (D)
Cations are formed by – (A) Gaining electrons (B) Losing electrons (C) Sharing electrons (D) None Answer: (B)
The number of covalent bonds in CH₄ is – (A) 1 (B) 2 (C) 3 (D) 4 Answer: (D)
Which of the following is biodegradable? (A) Plastic (B) DDT (C) Paper (D) Polythene Answer: (C)
The non-metal that conducts electricity is – (A) Sulfur (B) Phosphorus (C) Carbon (graphite) (D) Oxygen Answer: (C)
The element with lowest atomic radius is – (A) H (B) He (C) F (D) Li Answer: (B)
Alkali metals react vigorously with – (A) Oxygen (B) Hydrogen (C) Water (D) Nitrogen Answer: (C)
The number of atoms in 1 mole is – (A) 6.023 × 10²³ (B) 6.023 × 10²² (C) 1.66 × 10⁻²⁴ (D) 3.14 × 10⁻⁷ Answer: (A)
The chemical name of caustic potash is – (A) NaOH (B) KOH (C) Ca(OH)₂ (D) NH₄OH Answer: (B)
The metal found in blood pigment hemoglobin is – (A) Iron (B) Copper (C) Magnesium (D) Zinc Answer: (A)
The gas used for sterilization in hospitals is – (A) CO₂ (B) O₃ (C) N₂ (D) Cl₂ Answer: (B)
The foul smell of rotten eggs is due to – (A) H₂ (B) SO₂ (C) H₂S (D) NH₃ Answer: (C)
Who gave the periodic law? (A) Bohr (B) Mendeleev (C) Moseley (D) Dalton Answer: (B)
The process of depositing a layer of metal using electric current is – (A) Welding (B) Soldering (C) Electroplating (D) Refining Answer: (C)
Which acid is present in ant sting? (A) Oxalic acid (B) Acetic acid (C) Formic acid (D) Citric acid Answer: (C)
What is an alloy? (A) Compound of metals (B) Mixture of metals (C) Ore (D) Salt Answer: (B)
The formula of sodium thiosulfate is – (A) Na₂SO₄ (B) Na₂S₂O₃ (C) Na₂CO₃ (D) NaHSO₄ Answer: (B)
Which non-metal is liquid at room temperature? (A) Bromine (B) Iodine (C) Carbon (D) Sulfur Answer: (A)
Which gas is used in anesthesia? (A) CO₂ (B) CH₄ (C) N₂O (D) NH₃ Answer: (C)
The smallest particle of an element is – (A) Atom (B) Molecule (C) Ion (D) Proton Answer: (A)
Which metal is used to extract gold and silver? (A) Zinc (B) Copper (C) Mercury (D) Lead Answer: (C)
Which of the following is acidic in nature? (A) Lemon juice (B) Baking soda (C) Toothpaste (D) Soap Answer: (A)
The number of periods in the periodic table is – (A) 7 (B) 8 (C) 18 (D) 10 Answer: (A)
The metal found in chlorophyll is – (A) Iron (B) Calcium (C) Magnesium (D) Potassium Answer: (C)
Which salt is used in making glass? (A) Na₂SO₄ (B) Na₂CO₃ (C) NaCl (D) KCl Answer: (B)
Which of the following is an alkali metal? (A) Mg (B) Ca (C) Na (D) Al Answer: (C)
The formula of formaldehyde is – (A) HCOOH (B) CH₃OH (C) CH₂O (D) CH₃CHO Answer: (C)
Which property of metals allows them to be drawn into wires? (A) Ductility (B) Malleability (C) Conductivity (D) Hardness Answer: (A)
