Hogwarts trivia

Trivia #1
What's the name of this potion?
This potion has the colour of molten gold, and while exposed to the air, large drops will leap like goldfish above the surface without spilling. Felix Felicis

Trivia #2
Which book is this line from?
"Harry and Cho were now too embarrassed to look at each other, let alone talk to each other; what if Ron and Hermione started going out together, then split up? Could their friendship survive it? Harry remembered the few weeks when they had not been talking to each other in third year; he had not enjoyed trying to bridge the distance between them. And then, what if they didn't split up? What if they became like Bill and Fleur, and it became excrutiatingly embarrassing to be in their presence, so that he was shut out for good?" HP and the Half Blood Prince

Trivia #3
Who utters these words?
"Oh I am glad I'm not on duty. I wouldn't fancy having to go and tell the Irish they've got to stop celebrating." Arthrur Weasley