balance the equation

Question

Balance the equation Al2O3(s) + NaOH(l) --> Na3AIF6 + H20(g)

Answer 1

Assuming the equation to balance is actually

Al₂O₃ + NaOH + HF → Na₃AlF₆ + H₂O

First balance the Na, F and O atoms to give

Al₂O₃ + 3 NaOH + 6 HF → Na₃AlF₆ + 6 H₂O

The Al atoms aren't balanced so we put a coefficient of 2 in front of Na₃AlF₆ then double the coefficients in front of NaOH and HF giving

Al₂O₃ + 6 NaOH + 12 HF → 2 Na₃AlF₆ + 6 H₂O

Now everything balances except for O and H.

There are 9 O atoms and 18 H atoms on the left so we change the coefficient in front of H₂O on the right to a 9. This gives

Al₂O₃ + 6 NaOH + 12 HF → 2 Na₃AlF₆ + 9 H₂O 

and we have a balanced equation!