Acid-Base solutions and their effectiveness for deprotonation of NH4+

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Discussion Overview

The discussion revolves around the effectiveness of various acid-base solutions for the deprotonation of the ammonium ion (NH4+). Participants explore the relationship between pH, acidity, and basicity in determining which solution would effectively deprotonate NH4+, considering the implications of equilibrium constants (K) in this context.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant suggests that NH4+ is a strong acid and infers that it should react with the strongest base, which they identify as solution D due to its highest pH.
  • Another participant corrects the notion that NH4+ is a strong acid, questioning how to approach the problem under the assumption that K>1 indicates a reaction favoring products.
  • A different participant agrees that D is the strongest base among the options, citing its higher pH as indicative of its alkalinity.
  • Some participants express confusion about the relationship between strong acids and strong bases in the context of deprotonation, particularly regarding the role of pKa.
  • One participant reiterates the original question about the effectiveness of the solutions, emphasizing the need for a strong base to deprotonate NH4+.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether NH4+ should be considered a strong acid or how to effectively determine the best base for its deprotonation. Multiple competing views remain regarding the interpretation of pH values and the implications for acid-base strength.

Contextual Notes

There is uncertainty regarding the definitions of strong acids and bases in this context, as well as the implications of pKa and equilibrium constants on the effectiveness of the proposed solutions for deprotonation.

ada0713
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Consider the following solutions and their respective pH values. Which substance would be effective(K>1) for the deprotonation of NH4+ ?
0.1 M A, pH = 6.85
0.1 M B, pH = 7.22
0.1 M C, pH = 8.34
0.1 M D, pH = 11.88

1) A
2) B
3) C
4) D
5) none are effective

If the reaction to be effective
doesn't Strong acid have to react with strong base?
since NH4+ is strong acid, I thought it should react with the strongest
base among the four substances,
so i chose D, which has the highest pH value.

Is it right, or am I doing something wrong here?
 
Last edited:
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oh.. NH4+ is not a strong acid..
how do I approach this problem then?

If K>1, net direction is right,
then shouldn't the reactants be stonger acid and stronger base?
 
Last edited:
anyone?
 
Dissociation of ammonium as an acid is weak; I would guess the choice D is the strongest base allowed for you and that would be most effective in deprotonating the ammonium ion. I say it is the strongest base there because all of your choices are 0.1 Molar; and D has the highest pH (therefore most alkaline).
 
i thought NH4+ would be a strong acid. NH3 is a weak base, it's conjugate acid, NH4+ should then be strong.

but you still need the strongest base... therefore D
 
ada0713 said:
Consider the following solutions and their respective pH values. Which substance would be effective(K>1) for the deprotonation of NH4+ ?
0.1 M A, pH = 6.85
0.1 M B, pH = 7.22
0.1 M C, pH = 8.34
0.1 M D, pH = 11.88

1) A
2) B
3) C
4) D
5) none are effective

If the reaction to be effective
doesn't Strong acid have to react with strong base?
since NH4+ is strong acid, I thought it should react with the strongest
base among the four substances,
so i chose D, which has the highest pH value.

Is it right, or am I doing something wrong here?

Why do you think you were given the pH at a particular concentration? Have you studied the concept of pKa? What 'K' was referred to in the question "...(K>1)..."?
 

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