TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: When gas particles heat up, pressure increase.

SOLUTION: Does pressure increase or decrease when gas particles heat up?

PROBLEM: Humans have 23 pairs pairs of chromosomes.

SOLUTION: How many pairs of chromosomes do human have ?

PROBLEM: The binary halides are an important subclass of salts.

SOLUTION:
The binary halides are an important subclass of what?