Chemistry
Which of the following substances can act as a dehydrating as well as a drying agent.
- Oxalic acid
- Conc. nitric acid
- Washing soda
- Conc sulphuric acid
Answer
Conc sulphuric acid
Reason — Being hygroscopic sulphuric acid absorbs moisture but not enough to form a solution. Hence, it is a drying agent.
Sulphuric acid is a dehydrating agent as it can remove chemically combined water molecules from blue vitriol.
CuSO4.5H2O + H2SO4 ⇌ CuSO4 + 5H2O
Oxalic acid is an organic acid and does not act as a strong drying or dehydrating agent. Nitric acid is a strong acid and oxidising agent, but it is not mainly used as a drying or dehydrating agent. Sodium carbonate decahydrate is a basic salt used for cleaning, not for drying or dehydration.
Related Questions
The crystalline substance that does not contain water of crystallisation is:
- Plaster of paris
- Potash alum
- Potassium permanganate
- Epsom salt
Table salt becomes sticky in the presence of moisture because :
- It is deliquescent
- It is hygroscopic
- It contains impurities which are deliquescent
- It is a good drying agent.
Which of the following is a deliquescent salt ?
- CuSO4
- FeCl3
- KCl
- ZnSO4
If a salt on heating does not gives water vapour, then that salt is:
- Hygroscopic
- Deliquescent
- Hydrated
- Anhydrous