Which container protects hygroscopic chemicals from humidity?

• A. Beaker
• B. Pipette
• C. Graduated cylinder
• D. Desiccator

Answer: (D)

Hygroscopic materials pull moisture from the air, so they must be kept in a dry, sealed environment. A desiccator provides exactly that: it’s a sealed chamber that holds a desiccant, such as silica gel or anhydrous calcium chloride, which absorbs moisture from the air inside. This keeps the interior dry and protects hygroscopic chemicals from humidity. Some desiccators also have a stopcock to evacuate air and maintain the dry conditions.

Beakers, pipettes, and graduated cylinders aren’t designed to seal out humidity; they’re open or only loosely covered and can’t prevent water uptake, so they won’t protect hygroscopic substances like a desiccator does.