Transition Metals and Redox

What is a key characteristic of transition metals that allows them to act as catalysts?

• They have high melting points.

• They form colored compounds.

• They exhibit variable oxidation states.

• They are good conductors of electricity.

How does increasing the acidity of a solution generally affect the redox potential for a transition metal ion that requires hydrogen ions for reduction?

• It decreases the redox potential.

• It increases the redox potential.

• It has no effect on the redox potential.

• It makes the redox potential negative.

When vanadium (V+5) is progressively reduced by zinc in an acidic solution, what is the correct sequence of color changes observed?

• Yellow → Green → Blue → Violet

• Yellow → Blue → Green → Violet

• Violet → Green → Blue → Yellow

• Blue → Yellow → Green → Violet