Redox (Yr12 OCR)

Fe₂O₃ + 2Al --> 2Fe + Al₂O₃

Which statement is correct?

• Aluminium has been oxidised, iron (III) oxide has been reduced

• Aluminium has been reduced, iron (III) oxide has been oxidised

Fe₂O₃ + 2Al --> 2Fe + Al₂O₃

Fe has been reduced from:

• +3 to 0

• +6 to 0

• +3 to +1

• +6 to +1

CO₂ + C --> 2CO

Which statement is correct?

• Carbon is oxidised from 0 to +2. Carbon is reduced from +4 to +2.

• Carbon is reduced from 0 to +2. Carbon is oxidised from +4 to +2.

• Carbon is oxidised from +2 to +1. Carbon is reduced from +4 to +2.

2Na + 2H₂O --> 2NaOH + H₂

Which element is oxidised?

• Sodium

• Water

• Neither

2Na + 2H₂O --> 2NaOH + H₂

Which statement is correct?

• Hydrogen is oxidised from +1 to 0. Sodium is reduced from 0 to +1.

• Hydrogen is reduced from +1 to 0. Sodium is oxidised from 0 to +1.

• Hydrogen is reduced from +2 to 0. Sodium is oxidised from 0 to +2.

• Hydrogen is oxidised from +2 to 0. Sodium is reduced from 0 to +2.

2Cu²⁺ + 4I^- --> 2CuI + I₂

Have the copper ions been:

• Reduced from +2 to +1

• Oxidised from +2 to +1

• Reduced from 0 to +1

• Oxidised from 0 to +1

Cu₂O + H₂SO₄ --> CuSO₄ + H₂O + Cu

The copper (I) ions have been:

• Oxidised

• Reduced

• Both

• Neither

Ca + H₂ --> CaH₂

Hydrogen has been:

• reduced from 0 to +1

• oxidised from 0 to +1

• reduced from 0 to -1

• oxidised from 0 to -1

Cl₂ + 2OH^- Cl^- + ClO^- + H₂O

Chlorine has been

• Oxidised

• Reduced

• Both

• Neither

2MnO₄^- + 5C₂O₄^2- + 8H⁺ --> 2Mn²⁺ + 10CO₂ + 4H₂O

Which species has been reduced?

• manganate

• carbon

• oxygen

• hydrogen