What are the common experimental defects in high school chemistry experiments? (except that there is no tail gas collection, anti-back suction)

1. If liquid is generated when the test tube is heated, the nozzle should be inclined downward, otherwise it will burst.

2. Experiments that require a separatory funnel, distillation bottle, etc. Need to check for air leakage.

3. When liquid is used to generate gas, which will be introduced into the heated reactor, it should be dried first, otherwise it will be dangerous.

4. If the liquid boils when heated, zeolite should be added, otherwise there is a danger of boiling.