Question
Question: The ground glass stopper is often seen to get stuck in the neck of glass bottles containing aq \(NaO...
The ground glass stopper is often seen to get stuck in the neck of glass bottles containing aq NaOH solution This is due to:
(A) Formation of solid Na2CO3 around the neck of the bottle due to NaOH reacting with atmospheric CO2
(B) Formation of solid Na2SiO3 around the neck of the bottle
(C) Creation of partial vacuum due to highly hygroscopic nature of NaOH
(D) High coefficient of thermal expansion of glass
Solution
It is unwise to put sodium hydroxide, or any alkali solution in a glass bottle with a glass stopper without oiling the stopper with a little petroleum jelly, because the alkali can react with the carbon dioxide in the air producing carbonate crust which might block the stopper.
Complete step by step solution:
Sodium hydroxide attacks glass, making sodium silicate, which is also known as waterglass and is used as a cement. It depends on the NaOH concentration and how long the bottle is unused. However, it can be difficult to get open again The ground glass stopper is often seen to get stuck in the neck of glass bottles containing aq NaOH solution this is due to formation of solid Na2SiO3 around the neck of the bottle.
2NaOH(aq)+SiO2→Na2SiO3(s)+H2O
Here, Na2SiO3 fuses with glass so the ground glass stopper is often seen to get stuck in the neck of a glass bottle containing a NaOH solution.
Note: We would use a polypropylene stopper instead of glass stopper. Polypropylene is a type of thermoplastic polymer and is used in a variety of applications. With the use of polypropylene we can stop the formation of the solid Na2SiO3 around the neck and the stopper is not seen to get stuck in the neck of glass containing a NaOH solution.