Question

1. which of the following lab safety rules is not true?

be sure to dispose of all chemicals down the sink drain, rather than the trashcan.
when smelling a substance, be sure to waft it.
you may never eat in a science lab.
hot glass looks like cold glass, so always handle glassware with safety equipment.

Explanation:

• For the option "When smelling a substance, be sure to waft it", wafting is the correct safety practice to avoid inhaling harmful fumes directly, so this is a true rule.
• The rule "You may never eat in a science lab" is true because eating in a lab can lead to contamination of food with chemicals or vice versa, and also pose a safety risk.
• The statement "Hot glass looks like cold glass, so always handle glassware with safety equipment" is true as hot glass can cause burns and looks identical to cold glass, so safety equipment (like tongs or heat - resistant gloves) should be used.
• However, not all chemicals can be disposed of down the sink drain. Some chemicals are corrosive, toxic, or can react with the plumbing or the environment. For example, strong acids or bases, heavy metals, and organic solvents may require special disposal procedures, so the statement "Be sure to dispose of all chemicals down the sink drain, rather than the trashcan" is not true.

Answer:

A. Be sure to dispose of all chemicals down the sink drain, rather than the trashcan.