Which of the following is best described as an
acid-base reaction?
1. 2HgO -> 2 Hg + O2
2. NH3 + H2O -> NH+4 + OH−
3. KCl + NH4NO3 -> KNO3 + NH4Cl
4. Ca + 2H2O -> Ca(OH)2 + H2
5. NaCl + AgNO3 ->NaNO3 + AgCl
How do u tell if it is a salt or not?
Basically, salts are a combination of a cation and an anion. KNO3 is a salt, NaNO3, AgNO3, NaCl, NH4NO3, KCl, NH4Cl, etc in the above are salts. To really answer this question, one must know the definition of the acid/base being used.
The best way to determine if a chemical reaction is an acid-base reaction is to identify the presence of acids and bases and observe if they undergo a neutralization reaction resulting in the formation of salt and water.
Let's analyze the given options to identify the acid-base reactions:
1. 2HgO -> 2Hg + O2:
This is not an acid-base reaction as there are no acids or bases involved.
2. NH3 + H2O -> NH+4 + OH−:
This is an acid-base reaction as ammonia (NH3) behaves as a base by accepting a proton (H+) from water, forming the ammonium ion (NH+4) and hydroxide ion (OH−).
3. KCl + NH4NO3 -> KNO3 + NH4Cl:
This is not an acid-base reaction. It is a double displacement reaction where the cations and anions of the salts interchange.
4. Ca + 2H2O -> Ca(OH)2 + H2:
This is an acid-base reaction as water behaves both as an acid (donating H+) and a base (accepting OH−) resulting in the formation of calcium hydroxide (Ca(OH)2) and hydrogen gas (H2).
5. NaCl + AgNO3 -> NaNO3 + AgCl:
This is not an acid-base reaction. It is also a double displacement reaction where the cations and anions of the salts interchange.
To determine if a compound is a salt, you need to check if it is formed by the reaction between an acid and a base. Salts are formed when the cation of a base combines with the anion of an acid. In the given options, compounds like NH4Cl, KNO3, and NaNO3 are salts because they are formed by the combination of cations (NH+4, K+, Na+) and anions (Cl−, NO3−). On the other hand, compounds like Hg, Ca(OH)2, and AgCl are not salts as they are not formed by the reaction between an acid and a base.