Question

which is used to prevent locking of Stoppers and joints in chemical apparatus​

Answer 1

Ground glass joints are used in laboratories to quickly and easily fit leak-tight apparatus together from commonly available parts. For example, a round bottom flask, Liebig condenser, and oil bubbler with ground glass joints may be rapidly fitted together to reflux a reaction mixture. This is a large improvement compared with older methods of custom-made glassware, which was time-consuming and expensive, or the use of less chemical resistant and heat resistant corks or rubber bungs and glass tubes as joints, which took time to prepare as well.

Answer 2

Answer:

Ground glass joints.

Explanation:

"Ground glass joints,"  have frosted appearance. They are finely ground to a specific size (which makes them pricey) and feature exterior (female) and inner (male) joints to ensure a snug fit when connecting components. The first number represents the female joint's inner diameter (in millimetres) or the male joint's outer diameter (in millimetres).

When connecting pieces of ground glass, it's better if the joints are free of chemicals; otherwise, the compounds may react, causing the joints to "freeze" together or become detachable.

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