What happens when plaster of paris is treated with co2

) adding phosphoric acid, said phosphoric acid reacting with said calcium carbonate to release gaseous carbon dioxide bubbles, and said water providing water of hydration to said plaster of Paris to form gypsum that sets around said carbon dioxide bubbles thereby forming said foamed plaster.

1. and 2. question: in which equation? or i don't understand you, 3. a), 4. c), 5. c), 6. b), 7. d), 8. d) if small number is underlined(behind symbol) , b) if big number is underlined(in front of symbol)9. what is underlined there? 10. c)