Chemistry
The crystalline substance that does not contain water of crystallisation is:
- Plaster of paris
- Potash alum
- Potassium permanganate
- Epsom salt
Answer
Potassium permanganate
Reason — The crystalline shape of a substance is not necessarily the result of the presence of water of crystallisation. In fact, there are number of crystalline solids that crystallize from water without holding any water of crystallisation. For example: Potassium permanganate
Plaster of Paris contains water of crystallisation (it is a hydrated salt). Potassium alum contains 12 molecules of water of crystallisation. Magnesium sulphate heptahydrate contains 7 molecules of water of crystallisation.
Related Questions
With a rise in temperature, the solubility of sodium chloride will:
- Increase rapidly
- Decrease
- Remain the same
- Increase slightly
The solubility of which of the following substances decreases with a rise in temperature :
- Potassium chloride
- Hydrated sodium sulphate
- Calcium hydroxide
- Potassium nitrate
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 substances can act as a dehydrating as well as a drying agent.
- Oxalic acid
- Conc. nitric acid
- Washing soda
- Conc sulphuric acid