Question

What happens when : (give balanced chemical equations only)
1. Caustic soda reacts with carbon dioxide
2.caustic soda reacts with zinc hydroxide
3.potassium reacts with oxygen
4.sodium carbonate is fused with silicon dioxide
5. when bleaching powder reacts with hydrochloric acid

Answer 1

You probably should have this information from lecture notes or the text. Go through those first, then post what you don't understand here. The first equation is given here but you must balance it.
NaOH + CO2 ==> Na2CO3