97) What is the name of the process where carbonate ores are converted to oxides by heating in limited air?

A) Calcination
B) Electrolysis
C) Roasting
D) Smelting

98) Which of the following is an ore of mercury?

A) Hematite
B) Cinnabar
C) Galena
D) Bauxite

99) What kind of bond exists in a molecule of nitrogen (N₂)?

A) Single bond
B) Double bond
C) Triple bond
D) Ionic bond

100) What makes graphite a good conductor of electricity?

A) Presence of strong covalent bonds
B) Free electrons in its layered structure
C) Its rigid three-dimensional structure
D) Its slippery texture

101) What property allows carbon to form large molecules by bonding with itself?

A) Valency
B) Electronegativity
C) Catenation
D) Ionization