61. Which of the following substances has the highest melting point?

A) Ice
B) Iron
C) Copper
D) Diamond
Answer: D) Diamond

62. Which of the following is a weak acid?

A) HCl
B) H2SO4
C) CH3COOH
D) HNO3
Answer: C) CH3COOH

63. What is the main component of vinegar?

A) Hydrochloric Acid
B) Acetic Acid
C) Sulfuric Acid
D) Nitric Acid
Answer: B) Acetic Acid

64. Which of the following is a noble gas?

A) Neon
B) Chlorine
C) Nitrogen
D) Oxygen
Answer: A) Neon

65. Which of the following is a d-block element?

A) Sodium
B) Magnesium
C) Iron
D) Phosphorus
Answer: C) Iron

66. Which of the following has a trigonal planar structure?

A) CH4
B) BF3
C) NH3
D) H2O
Answer: B) BF3

67. Which element is used in the manufacture of matches?

A) Sulfur
B) Phosphorus
C) Carbon
D) Calcium
Answer: B) Phosphorus

68. What is the formula for ammonium ion?

A) NH3
B) NH4+
C) NO3-
D) NH2-
Answer: B) NH4+

69. Which of the following is a covalent compound?

A) NaCl
B) H2O
C) MgO
D) CaCO3
Answer: B) H2O

70. Which of the following elements is liquid at room temperature?

A) Sodium
B) Bromine
C) Fluorine
D) Carbon
Answer: B) Bromine