A salt solution can be acidic, basic, or neutral. when dissolved in water, which of the following salts will not affect the pH: KCl, FeCl3, NaNO3, CaCO3, LiF, and NH4Br?
Salts are made from acids and bases.
Those that are made from strong acids and strong bases will be neutral in water soln (have pH = 7 in water.)
Salts made from weak acids and strong bases will be basic in water soln.
Salts made from strong acids and weak bases will be acidic in water soln.
Salts made from weak acids and weak bases will be acid, basic, or neutral depending upon which is stronger; i.e., acid if Ka>Kb, basic if Kb>Ka, neutral if Ka=Kb.
To determine which of the salts will not affect the pH when dissolved in water, we need to consider the cation and anion of each salt.
KCl: When KCl is dissolved in water, it dissociates into K+ (cation) and Cl- (anion). Both K+ and Cl- are neutral ions, so KCl will not affect the pH.
FeCl3: FeCl3 dissociates into Fe3+ (cation) and Cl- (anion). Fe3+ is a neutral ion, while Cl- is a conjugate base of a strong acid (HCl) and does not affect the pH significantly. Therefore, FeCl3 will not affect the pH.
NaNO3: NaNO3 dissociates into Na+ (cation) and NO3- (anion). Both Na+ and NO3- are neutral ions, so NaNO3 will not affect the pH.
CaCO3: CaCO3 dissociates into Ca2+ (cation) and CO3^2- (anion). Ca2+ is a neutral ion, while CO3^2- is the conjugate base of a weak acid (H2CO3) and can slightly increase the pH. Therefore, CaCO3 may slightly affect the pH.
LiF: LiF dissociates into Li+ (cation) and F- (anion). Li+ is a neutral ion, while F- is the conjugate base of a weak acid (HF) and can slightly decrease the pH. Therefore, LiF may slightly affect the pH.
NH4Br: NH4Br dissociates into NH4+ (cation) and Br- (anion). NH4+ is the conjugate acid of a weak base (NH3), and Br- is a neutral ion. NH4+ can slightly decrease the pH, while Br- will not affect the pH significantly. Therefore, NH4Br may slightly affect the pH.
Based on the above analysis, KCl, FeCl3, and NaNO3 will not significantly affect the pH when dissolved in water. CaCO3, LiF, and NH4Br may slightly affect the pH.
To determine which of the given salts will not affect the pH when dissolved in water, we need to analyze the nature of each salt.
There are three types of salt solutions based on their effect on pH: acidic salts, basic salts, and neutral salts.
Acidic salts are formed by the combination of a strong acid and a weak base. These salts can release hydrogen ions (H+) into the solution, making the solution acidic.
Basic salts are formed by the combination of a strong base and a weak acid. These salts can release hydroxide ions (OH-) into the solution, making the solution basic.
Neutral salts are formed by the combination of a strong acid and a strong base, resulting in a neutral solution that does not affect the pH.
Now, let's analyze each salt:
1. KCl:
- K+ is derived from a strong base (KOH), which is neutral.
- Cl- is derived from a strong acid (HCl), which is also neutral.
Therefore, KCl is a neutral salt.
2. FeCl3:
- Fe3+ is derived from a strong base (Fe(OH)3), which is neutral.
- Cl- is derived from a strong acid (HCl), which is also neutral.
Therefore, FeCl3 is a neutral salt.
3. NaNO3:
- Na+ is derived from a strong base (NaOH), which is neutral.
- NO3- is derived from a strong acid (HNO3), which is also neutral.
Therefore, NaNO3 is a neutral salt.
4. CaCO3:
- Ca2+ is derived from a strong base (Ca(OH)2), which is neutral.
- CO3 2- is derived from a weak acid (H2CO3), making it basic.
Therefore, CaCO3 is a basic salt.
5. LiF:
- Li+ is derived from a strong base (LiOH), which is neutral.
- F- is derived from a weak acid (HF), making it basic.
Therefore, LiF is a basic salt.
6. NH4Br:
- NH4+ is derived from a strong base (NH4OH), making it acidic.
- Br- is derived from a strong acid (HBr), which is also neutral.
Therefore, NH4Br is an acidic salt.
Based on the analysis, the salts that will not affect the pH when dissolved in water are KCl, FeCl3, and NaNO3.