Question 1:

Which of the following statements is true about oxidation and reduction?

Explanation: Option B is correct. Oxidation is the loss of electrons, while reduction is the gain of electrons. Remember the mnemonic "OIL RIG" - Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons).

Question 2:

What is the oxidation number of oxygen in most compounds?

Explanation: Option D is correct. In most compounds, oxygen has an oxidation number of -2. However, there are exceptions such as peroxides (e.g., H2O2) where oxygen has an oxidation number of -1.

Question 3:

What is the oxidation number of hydrogen in most compounds?

Explanation: Option A is correct. In most compounds, hydrogen has an oxidation number of +1. However, there are exceptions such as metal hydrides (e.g., NaH) where hydrogen has an oxidation number of -1.

Question 4:

In the redox reaction: Zn + 2HCl → ZnCl2 + H2, which species is oxidized?

Explanation: Option A is correct. In the given redox reaction, zinc (Zn) is oxidized. It loses electrons and increases its oxidation number from 0 to +2 in ZnCl2.

Question 5:

In the redox reaction: Fe2O3 + 3CO → 2Fe + 3CO2, which species is reduced?

Explanation: Option C is correct. In the given redox reaction, iron (Fe) is reduced. It gains electrons and decreases its oxidation number from +3 to 0 in Fe.