Question

Of the following the commonly used as a laboratory desiccator is:
(A) \[N{a_2}C{O_3}\]
(B) \[CaC{l_2}\]
(C) \[NaCl\]
(D) None of the above.

Answer 1

Hint: Laboratory desiccator is a sealed container that contains desiccant which can absorb water molecules or moisture. In order to be a good desiccant, the substance should be inert, hygroscopic, and exist in a state of dryness and non-toxic. The above given chemical compounds which have all these properties can be used as a laboratory desiccant.

Complete step by step answer:
Desiccator is a glass container which can be sealed. Desiccator contains desiccant at the bottom of the glass vessel. Desiccant is the substance which is used to preserve moisture-sensitive chemicals. Above the desiccant, a level platform is placed.
Desiccant can absorb the moisture or water content from the chemicals which are placed inside it. Desiccators will always be dry due to the presence of desiccant. Beakers or chemicals which are heated are placed inside the desiccator, so that the desiccant present in it can cool them. If we want to obtain a precise value of our sample, we should not place the heated sample or beaker because it can absorb moisture from the air, thus making the value incorrect. Mostly hygroscopic chemicals should be kept inside the desiccator, in order to make the chemicals last longer.
 Desiccant which is used in the desiccator should contain these properties such as
- it should be inert
- it should be non-toxic
- water insoluble.
In the above given chemical compounds, the above given properties of desiccant are present in \[CaC{l_2}\].

Therefore, the correct answer is option (B) \[CaC{l_2}\].

Additional information:
The other desiccants which can be used in the desiccator are:
- Silica
- Activated charcoal
- \[CaS{O_4}\]

Note: We can use some humidity indicator to tell the degree of water-saturation of the desiccants because it will tell us when we would have to change the salt in the desiccants. Because the indicator will change its colour indicating that we have to replace the new salt.