TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Limestone is insoluble in water, so acid can dissolve it.

SOLUTION: Limestone is insoluble in water, so what can dissolve it?

PROBLEM: Urea is made in the liver and excreted in urine.

SOLUTION: What is made in the liver and excreted in urine?

PROBLEM: Balanced chemical reactions are balanced in terms of moles.

SOLUTION:
Balanced chemical reactions are balanced in what?