1. Which reagent is commonly used to dry phosphine gas?
A.
Concentrated sulfuric acid
B.
Aqueous sodium hydroxide
C.
Water
D.
Dilute hydrochloric acid
Correct Answer:
Concentrated sulfuric acid
Explanation:
Phosphine gas is dried by passing it through concentrated sulfuric acid, which removes moisture from the gas.
2. The purpose of passing phosphine gas through concentrated sulfuric acid is to remove which impurity?
A.
Moisture
B.
Hydrogen
C.
Nitrogen
D.
Oxygen
Correct Answer:
Moisture
Explanation:
Concentrated sulfuric acid acts as a drying agent and removes water vapour from phosphine gas.
3. Which substance acts as a drying agent for phosphine gas during its preparation?
A.
Concentrated H2SO4
B.
Dilute H2SO4
C.
Aqueous NH3
D.
Liquid water
Correct Answer:
Concentrated H2SO4
Explanation:
Concentrated sulfuric acid is used to dry phosphine because it removes moisture from the gas.
4. In the preparation of phosphine, the gas is dried by passing it through:
A.
Concentrated sulfuric acid
B.
Concentrated sodium hydroxide solution
C.
Dilute nitric acid
D.
A saturated salt solution
Correct Answer:
Concentrated sulfuric acid
Explanation:
A stream of phosphine is passed through concentrated sulfuric acid to eliminate water vapour.
5. Which of the following is the correct drying material for phosphine gas?
A.
Concentrated sulfuric acid
B.
Concentrated hydrochloric acid
C.
Dilute sulfuric acid
D.
Aqueous calcium hydroxide
Correct Answer:
Concentrated sulfuric acid
Explanation:
Concentrated sulfuric acid is a strong dehydrating agent and is used to dry phosphine gas.
6. What is the main function of concentrated sulfuric acid in the purification of phosphine gas?
A.
To remove moisture
B.
To produce phosphine
C.
To add hydrogen to phosphine
D.
To convert phosphine into phosphorus
Correct Answer:
To remove moisture
Explanation:
In this step, concentrated sulfuric acid removes water vapour and thereby dries the phosphine gas.
7. A sample of phosphine gas contains water vapour. Which treatment will dry it?
A.
Passing it through concentrated H2SO4
B.
Passing it through water
C.
Mixing it with dilute HCl
D.
Passing it through aqueous ammonia
Correct Answer:
Passing it through concentrated H2SO4
Explanation:
Passing phosphine through concentrated sulfuric acid removes its moisture and gives dry phosphine gas.
8. Which acid is used to dry phosphine gas in its laboratory preparation?
A.
Concentrated sulfuric acid
B.
Dilute sulfuric acid
C.
Concentrated nitric acid
D.
Dilute phosphoric acid
Correct Answer:
Concentrated sulfuric acid
Explanation:
Concentrated sulfuric acid is the standard acid drying agent used for phosphine gas.
9. Dry phosphine gas is obtained after removing which component from the gas mixture?
A.
Water vapour
B.
Phosphorus vapour
C.
Hydrogen chloride
D.
Carbon dioxide
Correct Answer:
Water vapour
Explanation:
The drying step specifically removes water vapour from the phosphine gas.
10. Which statement about drying phosphine gas is correct?
A.
It is dried using concentrated sulfuric acid.
B.
It is dried by bubbling through water.
C.
It is dried using dilute sulfuric acid.
D.
It is dried by mixing with aqueous ammonia.
Correct Answer:
It is dried using concentrated sulfuric acid.
Explanation:
Concentrated sulfuric acid removes moisture from phosphine and is therefore used for drying the gas.
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