[tiff8968]

I have two questions that I cant find and need help with

1. Why is it essential to protect the fermenting reaction from exposure to oxygen???

2. A tube has been placed in a solution of calcioum hydroxide (limewater). What is the reason for placing the tube in the limewater?

[Arkcon]

2. A tube has been placed in a solution of calcioum hydroxide (limewater). What is the reason for placing the tube in the limewater?

For this one, can you try to write a balanced chemical equation, and guess the products?  You might be able to figure out this answer on your own, the inorganic chemistry involved is pretty easy, and you'll be better off come exam time.