Understanding the weak base NH3 in water - .

In summary, the conversation discusses the behavior of a weak base, NH3, in water. It is stated that NH3 competes against both OH- and water to form NH4+ in a reaction. It is also noted that OH- is a more reactive base than water, as it would prefer to attack a weak acid over water in a solution.
  • #1
christian0710
409
9
Hi i have a general question concerning the behavior of a weak base NH3 in water.
If we have a reaction between a weak base and water

NH3 + H2O = NH4(+) + OH(-)

NH3 is a weak base with respect to the base ,OH(-), produced from water. This means that the lone pair of OH(-) will Attack a high procentage of the NH4+ that NH3 want’s to produce from water.

Is it correctly assumed that the weak base NH3 is actually competing against 2 bases in a water solution: It’s competing against OH because OH reacts with NH4+ but it also competes aginst water, because the following equilibrium must be true
NH4+ + H2O = H3O(+) + NH3
So actually NH4+ reacts with OH and H2O to form NH3…Correct?

A last question:
Is OH(-) a more reactive base than water? For instance if we have put a weak acid into water, would the OH(-) produced from waters autoinoization reaction prefer to attack the weak acid more than water itself?
 
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  • #2
Yes, it is correctly assumed that the weak base NH3 is competing against two bases in a water solution. NH4+ will react with both OH− and H2O to form NH3. Yes, OH− is a more reactive base than water. If a weak acid is added to water, OH− would be more likely to attack the weak acid than water itself.
 

FAQ: Understanding the weak base NH3 in water - .

1. What is the chemical formula for NH3?

The chemical formula for NH3 is ammonia, which is composed of one nitrogen atom and three hydrogen atoms.

2. How does NH3 act as a weak base in water?

NH3 is a weak base in water because it can accept a proton from water to form NH4+ and OH-. This is known as the Bronsted-Lowry theory of acids and bases.

3. How does the concentration of NH3 affect its basicity in water?

The concentration of NH3 in water directly affects its basicity. The higher the concentration of NH3, the higher the concentration of OH- ions produced, making the solution more basic.

4. What is the pH of a solution containing NH3 and water?

The pH of a solution containing NH3 and water depends on the concentration of NH3. At low concentrations, the pH will be slightly basic, while at high concentrations, the pH may be more alkaline.

5. How does temperature affect the basicity of NH3 in water?

Increasing the temperature of a solution containing NH3 and water will increase the basicity of the solution. This is because the reaction between NH3 and water is endothermic, meaning it requires heat to occur.

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