GRACE AKELLO
Oct 7
Magnesium chloride dissolves in water to form a neutral solution while aluminum (111) chloride forms an acidic solution. Explain?
Chemistry
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ChatGPT
Oct 7
When magnesium chloride (MgCl2) dissolves in water, it dissociates into magnesium ions (Mg2+) and chloride ions (Cl-). Both of these ions are spectator ions and do not react with water. Therefore, the solution remains neutral.
On the other hand, when aluminum chloride (AlCl3) dissolves in water, it also dissociates into aluminum ions (Al3+) and chloride ions (Cl-). However, the aluminum ions can react with water to form aluminum hydroxide (Al(OH)3) and hydrogen ions (H+). This reaction results in the formation of an acidic solution.
AlCl3 + 3H2O -> Al(OH)3 + 3H+
Therefore, the presence of aluminum ions in the solution leads to the formation of an acidic solution.
On the other hand, when aluminum chloride (AlCl3) dissolves in water, it also dissociates into aluminum ions (Al3+) and chloride ions (Cl-). However, the aluminum ions can react with water to form aluminum hydroxide (Al(OH)3) and hydrogen ions (H+). This reaction results in the formation of an acidic solution.
AlCl3 + 3H2O -> Al(OH)3 + 3H+
Therefore, the presence of aluminum ions in the solution leads to the formation of an acidic solution.
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Google Gemini AI
Oct 7
Magnesium Chloride Forms a Neutral Solution:
- Ionization: When magnesium chloride (MgCl₂) dissolves in water, it undergoes hydrolysis, where water molecules break down the ions:
```
MgCl₂ + H₂O → Mg²⁺ + 2Cl⁻ + OH⁻
```
- Hydroxide Ion Removal: The hydroxide ions (OH⁻) produced in the reaction react with hydrogen ions (H⁺) from water to form water molecules:
```
OH⁻ + H⁺ → H₂O
```
- Neutralization: The removal of hydroxide ions from the solution prevents the formation of excess hydrogen ions, resulting in a neutral pH.
Aluminum (III) Chloride Forms an Acidic Solution:
- Hydrolysis: Aluminum (III) chloride (AlCl₃) also undergoes hydrolysis in water. However, the reaction is more extensive than for magnesium chloride:
```
AlCl₃ + 3H₂O → Al(OH)₃ + 3H⁺ + 3Cl⁻
```
- Proton Release: In this reaction, water molecules act as both a base and an acid. They donate hydroxide ions to form aluminum hydroxide (Al(OH)₃), which is insoluble and precipitates out of the solution. This process releases hydrogen ions (H⁺) into the solution.
- Acidic pH: The excess hydrogen ions lower the pH of the solution, making it acidic.
Summary:
The difference in acidity between magnesium chloride and aluminum (III) chloride solutions lies in their hydrolysis reactions. Magnesium chloride forms a neutral solution because the hydrolysis reaction consumes hydroxide ions, which would otherwise form hydrogen ions and lower the pH. Conversely, aluminum (III) chloride undergoes extensive hydrolysis, releasing hydrogen ions and resulting in an acidic solution.
- Ionization: When magnesium chloride (MgCl₂) dissolves in water, it undergoes hydrolysis, where water molecules break down the ions:
```
MgCl₂ + H₂O → Mg²⁺ + 2Cl⁻ + OH⁻
```
- Hydroxide Ion Removal: The hydroxide ions (OH⁻) produced in the reaction react with hydrogen ions (H⁺) from water to form water molecules:
```
OH⁻ + H⁺ → H₂O
```
- Neutralization: The removal of hydroxide ions from the solution prevents the formation of excess hydrogen ions, resulting in a neutral pH.
Aluminum (III) Chloride Forms an Acidic Solution:
- Hydrolysis: Aluminum (III) chloride (AlCl₃) also undergoes hydrolysis in water. However, the reaction is more extensive than for magnesium chloride:
```
AlCl₃ + 3H₂O → Al(OH)₃ + 3H⁺ + 3Cl⁻
```
- Proton Release: In this reaction, water molecules act as both a base and an acid. They donate hydroxide ions to form aluminum hydroxide (Al(OH)₃), which is insoluble and precipitates out of the solution. This process releases hydrogen ions (H⁺) into the solution.
- Acidic pH: The excess hydrogen ions lower the pH of the solution, making it acidic.
Summary:
The difference in acidity between magnesium chloride and aluminum (III) chloride solutions lies in their hydrolysis reactions. Magnesium chloride forms a neutral solution because the hydrolysis reaction consumes hydroxide ions, which would otherwise form hydrogen ions and lower the pH. Conversely, aluminum (III) chloride undergoes extensive hydrolysis, releasing hydrogen ions and resulting in an acidic solution.
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