Most solutions used in schools are made easily with few safety precautions.
Many solutions, however, require considerable care. Toxicity, for example, is a serious problem. Persons preparing solutions need to follow some guidelines about hygiene.
Some seemingly ordinary solutions can be extremely difficult to prepare. For example, making 6 M H2SO4 from concentrated H2SO4 and water is very dangerous. (The acid must be added slowly to water to avoid spattering.)
