Redox Part 1

What are the correct definitions of reduction and oxidation respectively?

• loss of hydrogen, loss of oxygen

• loss of hydrogen, gain of oxygen

• gain of hydrogen, gain of oxygen

• gain of hydrogen, loss of oxygen

Which substance has been oxidised in the following reaction?

Fe₃O₄ + 4H₂ -> 3Fe + 4H₂O

• Fe₃O₄

• H₂

• Fe

• H₂O

Which of the following explains why H₂ is oxidised in the following reaction?

Fe₃O₄ + 4H₂ -> 3Fe + 4H₂O

• It gains oxygen to form H₂O.

• It loses oxygen to form Fe.

• It gains hydrogen to form H₂O.

• It loses hydrogen to form Fe.

Which substance is the oxidising agent in the following reaction?

CuO + H₂ -> Cu + H₂O

• CuO

• H₂

• Cu

• H₂O

Which of the following best explains why CuO is the oxidising agent?

CuO + H₂ -> Cu + H₂O

• CuO is being reduced to form Cu.

• CuO loses oxygen to form Cu.

• CuO causes H₂ to gain oxygen to form H₂O.

• CuO causes H₂ to lose oxygen to form H₂O.

Which substance has been oxidised?

MnO₂ + 4HCl -> MnCl₂ + Cl₂ + 2H₂O

• MnO₂

• HCl

• MnCl₂

• H₂O

Which of the following best explains why HCl is oxidized?

MnO₂ + 4HCl -> MnCl₂ + Cl₂ + 2H₂O

• It gains oxygen to form H₂O.

• It loses hydrogen to form Cl₂.

• It loses hydrogen to form MnCl₂.

When sodium atom becomes sodium ion (Na⁺), it gains electron.

• True

• False

When chlorine atom becomes chloride ion (Cl^-), it gains electrons.

• True

• False

When Fe²⁺ ion becomes Fe³⁺ ion, it loses electron.

• True

• False