What are close-toed shoes least likely to provide protection against?

hydrogen gas produced during a reaction

spilled water from a hot-water bath

broken glass from a dropped test tube

acid leaking from a cracked beaker

Hydrogen gas is harmless to your feet so since you don't need protection against it that seems the best answer.

Answer: Hydrogen gas produced during a reaction

Explanation:

A chemical lab is a place where potential hazards oriented to the use of the chemicals can happen. These chemicals can cause injuries to the skin when come in contact directly or indirectly. Therefore, protective safety measures should be taken so as to protect oneself while working in a chemical lab.

Among the options given, hydrogen gas produced during a reaction is the correct option. This is because of the fact that close-toed shoes can provide protection against all types of chemical fluids. But the gases like hydrogen gas are reactive and they are permeable inside the shoe material hence, may cause damage.