1. What is the solubility of phosphine (PH3) in water?
A.
Highly soluble
B.
Sparingly soluble
C.
Completely insoluble
D.
Soluble only in boiling water
Correct Answer:
Sparingly soluble
Explanation:
Phosphine is sparingly soluble in water, so only a small amount dissolves in it.
2. Which method is suitable for collecting phosphine because of its low solubility in water?
A.
Collection over water
B.
Collection by dissolving in water
C.
Collection only in aqueous solution
D.
Collection by neutralizing with water
Correct Answer:
Collection over water
Explanation:
Since phosphine is sparingly soluble in water, it can be collected over water with limited loss.
3. Why can phosphine be collected over water?
A.
It reacts rapidly with water
B.
It is highly soluble in water
C.
It is sparingly soluble in water
D.
It changes water into steam
Correct Answer:
It is sparingly soluble in water
Explanation:
A gas suitable for collection over water should not dissolve appreciably in water. Phosphine is sparingly soluble.
4. Which gas property would make collection of phosphine over water unsuitable?
A.
Very high solubility in water
B.
Low solubility in water
C.
Slight solubility in water
D.
Limited dissolution in water
Correct Answer:
Very high solubility in water
Explanation:
If phosphine were very highly soluble in water, most of the gas would dissolve instead of being collected.
5. Compared with a highly water-soluble gas, phosphine suffers what limitation during collection over water?
A.
It is lost completely in water
B.
Only a small amount may dissolve in water
C.
It cannot occupy the collection vessel
D.
It immediately forms ice in water
Correct Answer:
Only a small amount may dissolve in water
Explanation:
Because phosphine is sparingly soluble, a small amount can dissolve, but most of the gas remains available for collection.
6. Which observation supports the use of water displacement for collecting phosphine?
A.
Phosphine dissolves rapidly in water
B.
Phosphine is sparingly soluble in water
C.
Phosphine reacts completely with water
D.
Phosphine is produced only as a liquid
Correct Answer:
Phosphine is sparingly soluble in water
Explanation:
The low water solubility of phosphine allows it to remain largely as a gas during collection over water.
7. If phosphine were collected by passing it through a large volume of water, what would happen?
A.
A small quantity would dissolve in the water
B.
All phosphine would become solid
C.
The water would produce phosphine continuously
D.
Phosphine would become completely insoluble in every solvent
Correct Answer:
A small quantity would dissolve in the water
Explanation:
Phosphine is sparingly soluble, so some gas dissolves when it contacts water, although it is not lost completely.
8. Which statement about collecting phosphine over water is correct?
A.
It is impossible because phosphine is highly soluble
B.
It is possible because phosphine is sparingly soluble
C.
It is impossible because phosphine is a liquid
D.
It is possible only because phosphine reacts with water
Correct Answer:
It is possible because phosphine is sparingly soluble
Explanation:
The sparing solubility of phosphine makes collection over water possible.
9. What would be the main loss of phosphine during collection over water?
A.
A small amount dissolving in water
B.
The entire gas turning into oxygen
C.
The gas becoming a metal
D.
The water converting all the gas into hydrogen
Correct Answer:
A small amount dissolving in water
Explanation:
Although phosphine can be collected over water, its slight solubility causes a small loss through dissolution.
10. Which description best explains the water-collection behavior of phosphine?
A.
It is highly soluble, so it must be collected in water
B.
It is sparingly soluble, so it can be collected over water
C.
It is completely insoluble, so water has no contact with it
D.
It reacts violently with water, so it is collected under water
Correct Answer:
It is sparingly soluble, so it can be collected over water
Explanation:
Phosphine's sparing solubility means that most of the gas does not dissolve and can be collected by displacement of water.
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