Following guidance from the Health and Safety Executive most education employers have adopted various nationally available texts as the basis for their model risk assessments. However, teachers must still verify that what they propose to do confirms with any code of practice produced by their employer. You also need to consider your local circumstances. In most of the publications listed above there are suggestions as to whether an activity should be a teacher demonstration only, or could be done by students of various ages. Your employer will probably expect you to follow this guidance.
Teachers tend to think of eye protection as the main control measure to prevent injury.
In fact, personal protective equipment, such as goggles or safety spectacles, is meant to protect from the unexpected. If you expect a problem, more stringent controls are needed. A range of control measures may be adopted, the following being the most common. The importance of lower concentrations is not always appreciated, but if solutions are suitably dilute they are classified as irritant rather than corrosive. Safety spectacles give less protection, but may be adequate if nothing which is classed as corrosive or toxic is in use.