1. Which method is used to collect phosphine gas during its preparation?
A.
Collection over water
B.
Collection over mercury
C.
Downward displacement of air
D.
Upward displacement of air
Correct Answer:
Collection over water
Explanation:
Phosphine is collected over water because it is only slightly soluble in water.
2. Why can phosphine be collected over water?
A.
It is highly soluble in water
B.
It is nearly insoluble in water
C.
It reacts rapidly with water
D.
It is heavier than water
Correct Answer:
It is nearly insoluble in water
Explanation:
A gas can be collected over water when it does not dissolve appreciably in water. Phosphine is nearly insoluble in water.
3. In the gas collection of phosphine, the gas is generally collected in a container filled with:
A.
Water
B.
Concentrated sulfuric acid
C.
Sodium hydroxide solution
D.
Ethanol
Correct Answer:
Water
Explanation:
Phosphine is collected in a container filled with water because its low solubility permits collection by displacement of water.
4. The collection of phosphine over water is based mainly on its:
A.
High density
B.
Low melting point
C.
Low solubility in water
D.
Strong acidic nature
Correct Answer:
Low solubility in water
Explanation:
The gas collection method depends on phosphine having very low solubility in water.
5. Which liquid is most suitable for collecting phosphine by displacement?
A.
Water
B.
Liquid ammonia
C.
Concentrated nitric acid
D.
Bromine water
Correct Answer:
Water
Explanation:
Water is suitable because phosphine does not dissolve significantly in it under the collection conditions.
6. When phosphine is collected over water, it mainly displaces:
A.
Hydrogen
B.
Water
C.
Oxygen
D.
Carbon dioxide
Correct Answer:
Water
Explanation:
In collection over water, the produced phosphine gas occupies the space and displaces the water from the gas jar.
7. Which property of phosphine makes collection over water possible?
A.
It is highly reactive with water
B.
It is nearly insoluble in water
C.
It is a liquid at room temperature
D.
It has a very high boiling point
Correct Answer:
It is nearly insoluble in water
Explanation:
The low solubility of phosphine in water allows the gas to remain in the collecting vessel instead of dissolving.
8. The gas jar used for collecting phosphine over water is initially:
A.
Filled with water
B.
Filled with concentrated acid
C.
Filled with mercury vapour
D.
Completely filled with air
Correct Answer:
Filled with water
Explanation:
For collection over water, the gas jar is filled with water, which is then displaced by phosphine gas.
9. Which statement about the collection of phosphine is correct?
A.
It is collected over water because it is nearly insoluble in water.
B.
It is collected over water because it is highly soluble in water.
C.
It cannot be collected by displacement of water.
D.
It dissolves completely in water during collection.
Correct Answer:
It is collected over water because it is nearly insoluble in water.
Explanation:
Phosphine is collected by displacement of water because it has very low solubility in water.
10. What is the simplest description of the gas collection method used for phosphine?
A.
Collection by displacement of water
B.
Collection by freezing the gas
C.
Collection by absorption in water
D.
Collection by condensation into a liquid
Correct Answer:
Collection by displacement of water
Explanation:
Phosphine is collected by displacement of water since it is nearly insoluble in water.
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