Answers:
c. oxygen gas
d. chlorine gas
e. hydrogen gas
Justification:
Single displacement reactions are those reactions in which the atoms of one element substitute (replace or displace) the atoms of other element in a compound.
The representación of this ind of reactions is:
- A + BX → AX + B: the atoms of the element A displace the atoms of the element B in the compound BX. As result, the element B stands separated after the reaction.
The conditions for a single displacemente reactions are:
- One single element react with a compound
- The reactant single element will form part of a new compound
- One single element is removed from the compound
- The one single element removed from the compound stands as a separated product.
- It is a more active element displaces a less active element from the compound.
In the giiven statement, the element displaced will be as a gaseous product.
Ammonia is not a single element, but the compound with the formula NH₃, so it is not the result of a single displacement reaction, and it is not a possibility (discarded)
Air is not either a single element nor a compound, so it is not the result of a single displacemente reaction, and it is not a possibility (discarded).
Since oxygen is one of the most reactive non-metal elements, oxygen gas is usually the result of a decomposition reaction and not of a single displacement reaction.
Decomposition reactions are those in which a single compound breaks down into two or more simpler substances (elements and/or compounds). Some examples of decompositon reaction in which oxygen gas evolves as a product are:
- The decomposition of water into hydrogen and oxygen gases.
- The decomposition of hydrogen peroxide to form oxygen gas and water.
- The decomposition of solid potassium chlorate to form solid potassum chloride and oxygen gas.
Nevertheless, fluorine is more active than oxygen, and so it can oxidises water according to this single replacement reaction:
As you see, fluorine displaces oxygen, so this is one of the right choices.
Regarding chlorine, being it less active than fluorine (fluorine is the most active halogen and the most active gas) you can predict without doubt that it can be displaced by flouorine. And so, chloringe gas is a right choice too.
The evolution hydrogen gas is a typical example of single displacement reactions and can be seen in this example:
- 2Li(s) + 2H₂O → 2LiOH + H₂(g)↑
Hence, hydrogen gas is one of the right options.
Conclusion: we have tested the choices one by one and the result is that the possibilities of the composition of those gas bubbles are:
c.oxygen gas
d.chlorine gas
e. hydrogen gas
