Addition of 6 M HCl to which substance will NOT result in gas evolution?
A. Al
B. Zn
C. K2CO3
D. NaNO3
The answer is D. Can someone explain how to arrive at that answer, please?
The Correct Answer and Explanation is:
The question asks which substance, when treated with 6 M hydrochloric acid (HCl), will not produce gas. The answer is D. NaNO3 (sodium nitrate). To understand why this is the case, let’s analyze each option.
A. Al (Aluminum)
Aluminum is a reactive metal that can react with hydrochloric acid. The reaction produces aluminum chloride and hydrogen gas:
[
2Al + 6HCl \rightarrow 2AlCl_3 + 3H_2(g)
]
Here, hydrogen gas ((H_2)) is evolved.
B. Zn (Zinc)
Zinc also reacts with hydrochloric acid. The reaction produces zinc chloride and hydrogen gas:
[
Zn + 2HCl \rightarrow ZnCl_2 + H_2(g)
]
Again, hydrogen gas ((H_2)) is produced in this reaction.
C. K2CO3 (Potassium Carbonate)
Potassium carbonate is a carbonate salt that reacts with hydrochloric acid, resulting in the formation of potassium chloride, water, and carbon dioxide gas:
[
K_2CO_3 + 2HCl \rightarrow 2KCl + H_2O + CO_2(g)
]
In this case, carbon dioxide ((CO_2)) gas is evolved.
D. NaNO3 (Sodium Nitrate)
Sodium nitrate is a salt that does not react with hydrochloric acid in a way that produces gas. When sodium nitrate is mixed with hydrochloric acid, the main reactions involve the dissolution of sodium nitrate and potentially some minor acid-base reactions, but no gaseous products are formed:
[
NaNO_3 + HCl \rightarrow NaCl + HNO_3
]
The products are sodium chloride (table salt) and nitric acid, but there is no evolution of gas in this reaction.
Conclusion
In summary, options A, B, and C all lead to the evolution of gas when treated with 6 M HCl, either hydrogen or carbon dioxide. However, D. NaNO3 does not result in any gas evolution when reacted with HCl. Therefore, the correct answer is D, as it is the only substance among the choices that does not produce a gas upon reaction with hydrochloric acid.