Question

which safety precaution is recommended when a liquid is being heated in a test tube? 1 when holding the test tube, keep fingers closest to the open end of the tube. 2 direct the flame of the burner into the open end of the test tube. 3 stopper the test tube with a rubber stopper. 4 wear goggles and a laboratory apron.

Explanation:

Wearing goggles protects eyes from splashes or fumes, and an apron protects clothing from spills or chemical stains when heating a liquid in a test - tube. Keeping fingers close to the open end can cause burns, directing the flame into the open end is dangerous as it can cause splashing or explosion, and stoppering the test - tube can cause pressure build - up and explosion.

Answer:

1. Wear goggles and a laboratory apron.