Can someone please check if I have written and balanced the reaction properly?

Question

1.In 1774 Joesph Priestley discovered oxygen by decomposing the oxide of mercury.

2HgO = 2 Hg + O2

2. Slaked lime precipitates magnesium ions from hard water.

Ca(OH)2 + Mg(HCO3)2 = Ca(HCO3)2 + Mg(OH)2

Answer 1

looks good to me.

Answer 2

Thank you!