d and f BLOCK ELEMENTS

Which of the following interstitial compounds approaches the hardness of diamond?

• TiC
• Mn₄N
• Some borides
• Fe₃H

What is the typical composition range for the non-stoichiometric compound VHₓ?

• x = 1.0
• x = 2.0
• x = 0.56
• x = 0.0

Why are interstitial compounds like TiC and Mn4N chemically inert?

• They are noble metals
• They are purely ionic
• The strong metal-interstitial atom interactions make them stable
• They lack d-electrons

Which of the following best describes the composition of interstitial compounds like TiH1.7?

• Always stoichiometric
• Ionic in nature
• Non-stoichiometric
• Covalent network solid

What happens to the activation energy of a reaction when a suitable catalyst is present?

• It increases
• It remains the same
• It decreases
• It becomes zero