IB Multiple Choice - Valence & Ions

Chemistry: IB Diploma Higher Level, topic 2.6.4

Test yourself on IB Multiple Choice - Valence & Ions

Which ionic compound would be formed in the reaction between ammonium hydroxide and sulfuric acid?
Superoxide dismutase is an enzyme that forms the compound hydrogen peroxide (H₂O₂) from two protons and a peroxide ion. Hydrogen peroxide has an important role in immune cells as a defense mechanism.

Using the information above, predict the formula of the ionic compound formed between the lithium-ion and the peroxide ion.
A clumsy scientist finds a bottle labeled "BX₃" lying around in the lab. Which of the following could be the identity of element X?
What would you expect the formula of aluminum carbide to be?
The gemstone sapphire is mostly a compound of aluminum and oxygen that contains aluminum cations and oxygen anions.

What is the formula of this compound?