How many lone pairs are around the central atom in the Lewis formula for the
hydrogen sulfate ion, HSO4-?

The answer to your question is None, sulfur share of its electrons

Explanation:

Just remember:

Sulfur, S, has 6 electrons in its outermost shell

Hydrogen, H, has 1 electron in its outermost shell

Oxygen, O, has 6 electrons in its outermost shell

See the picture below

The electrons of sulfur are in blue

The electrons of oxygen are in red

The electron in hydrogen is in yellow

Sulfur is the central atom and it shares all its electrons with the oxygen.

r just means there's a number of carbon in teh chain. for example rcooh means that after x number of carbon, the chain ends with cooh.

explanation:

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .