What should be done immediately if concentrated acid is spilled on the floor?

When concentrated acid is spilled on the floor, it is crucial to handle the situation with care to prevent further hazards. The immediate action should involve washing the spill with water and neutralizing it with sodium bicarbonate. Water is used to dilute the acid, reducing its concentration and potential for harm, while sodium bicarbonate serves as a buffer to neutralize the acidic pH.

Neutralization is an essential step because concentrated acids can cause severe burns, react violently with certain substances, and release harmful fumes. By neutralizing the acid, you convert it to a less harmful substance, creating a safer environment.

The other options are not advisable. Allowing the acid to evaporate can release toxic vapors into the air, posing health risks. Covering the spill with sand might contain the acid temporarily but won't neutralize it; this can lead to the risk of accidental contact or further reaction with other materials. Relying solely on professional cleanup is also not practical for an immediate response; action should be taken quickly to minimize the hazard before wait for assistance. Thus, washing and neutralizing is the most effective and responsible course of action to ensure safety.