Which of the following is a balanced chemical equation?
• MgF 2 + Li 2CO3 →→→→ MgCO 3 + LIF
• 2AI + 6HCI →→→→ 3H 2 + AICI 3
• P 4 + 30 2 →→→→ 2P 20 3
• CH 4 + 20 2 →→→→ CO 2 + H