A filtering flask, also known as a vacuum flask, is a specialized laboratory glassware used for rapid filtration of liquids. Let’s delve into the details:

1. Design and Purpose:

   • Filtering flasks typically have a conical shape with a flat bottom, a tapered neck, and a sidearm.
   • They are designed for use in vacuum filtration procedures.
   • The thick walls of these flasks allow them to withstand pressure under vacuum.

2. Material:

   • Borosilicate glass is the most common material used for manufacturing filtering flasks.
   • Borosilicate glass is durable, heat-resistant, and chemically inert, making it suitable for various laboratory applications.
   • In some cases, filtering flasks can also be made from other materials, such as polystyrene.

3. Features:

   • Graduated and ungraduated varieties are available.
   • The sidearm of the flask can be integral or detachable.
   • Detachable sidearms often have barb-like rings for connecting to vacuum tubing.
   • Filtering flasks are sometimes referred to as Buchner flasks, suction flasks, Kitasato flasks, or side-arm flasks.

4. Applications:

   • Filtering flasks are commonly used with other accessories, such as Buchner funnels.
   • Buchner funnels fit through a rubber bung or a Buchner ring attached to the sidearm.
   • These flasks facilitate efficient liquid filtration in various scientific and research settings.

5. Variety:

   • Filtering flasks come in a variety of volumes and socket sizes.
   • They serve as essential tools in laboratories for tasks like separating solids from liquids.