With luck, a chemical manufacturer can reuse unreacted or inopportunely reacted materials or these may be sold to other companies for reuse. Solution Chemistry Chemicals are by far easier to handle in solutions than in any other form. Solutions can be diluted to deliver inconceivably small amounts of their cargo, if that's required. Liquids take the shape of whatever container they're placed in, making their measurement easy against standardized volume markings. Solutions flow easily and can thus form a stream in industrial processes.
Solutions often intermix completely, thus ensuring intimate contact of their contents.
In contrast, gases and solids are a pain to work with. Gases keep trying to escape from whatever contains them, sometimes explosively. Their reaction vessels must be pressurized and are more expensive than solution vessels. Solids are often recalcitrant about mixing well. All in all, solutions are a real blessing.