Label or a placard colored black and white with a skull and crossbones falls under which class

The correct answer is class-6 toxic and infectious components.

Explanation:

A placard or a label colored black and white with a skull and crossbones comes under class-6 health hazards. The class-6 is further sub differential into two categories, that is, class 6.1 and class 6.2.  

Class 6.1 signifies toxic substances, which possess the tendencies to cause serious injury or death or harm human health is inhaled or swallowed or coming in contact with skin.  

Class 6.2 comprises infectious substances, which are anticipated to constitute pathogens. The pathogens are illustrated as microbes that can result in diseases in animals or humans.