Neutralization Reactions: NaOH + HCl & NH3 + HCl

  • Thread starter Thread starter DarylMBCP
  • Start date Start date
  • Tags Tags
    Hcl Reactions
Click For Summary

Discussion Overview

The discussion revolves around neutralization reactions, specifically the reactions of NaOH with HCl and NH3 with HCl. Participants explore the theoretical implications of these reactions under different acid-base theories, including Brønsted–Lowry theory, and question the expected products of these reactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question why NaOH does not become NaH2O after accepting an H+ ion from HCl, given that NaOH is a base and should act as a proton acceptor according to Brønsted–Lowry theory.
  • There is a discussion about the dissociation of NaOH in water and whether it can still react as a base.
  • Participants propose that when NH3 reacts with HCl, the products are NH4+ and Cl-, but there is uncertainty about the presence of OH- in this reaction.
  • Some argue that the reaction between NH3 and HCl does not always yield a salt and water, raising questions about when this rule applies.
  • There is a clarification that NH4+ and Cl- are not a conjugate acid-base pair, as they differ by more than one proton.
  • Participants discuss the limitations of the Arrhenius definition of acids and bases in explaining the behavior of ammonia in reactions.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the reactions and the definitions of acids and bases. There is no consensus on the implications of these reactions or the definitions being applied.

Contextual Notes

Some participants highlight the limitations of the Arrhenius definition when applied to ammonia, suggesting that a broader understanding through Brønsted-Lowry theory may be necessary. There are unresolved questions regarding the nature of products in acid-base reactions.

Who May Find This Useful

This discussion may be of interest to students and individuals seeking to understand the complexities of acid-base reactions and the application of different theoretical frameworks in chemistry.

DarylMBCP
Messages
89
Reaction score
0

Homework Statement


An acid and a base is supposed to form a salt and water during a neutralization reaction such as NaOH + HCl --> NaCl + H2O. However, based on Brønsted–Lowry acid-base theory, shouldn't NaOH become NaH2O or something like that after accepting an H+ ion from HCl since the base is a proton acceptor? Why does the OH- ion from NaOH get separated?

My next question is...
What is the result when the base, NH3 reacts with the acid HCl, for example? Is the result NH4+ and Cl-?
 
Physics news on Phys.org
NaOH in water is fully dissociated. What is a proton acceptor in this solution?
 
In Brownsted- Lowry Theory, bases are said to be proton acceptors and acids are said to be proton donors and since NaOH is a base in this solution, shouldn't it receive a H+ion from HCl, which is an acid? When NH3, a base and H2O react, NH4+ and OH- are produced. In this case, a H+ ion is transferred from H2O to NH3 whereas in the NaOH and HCl reaction, a H+ ion is not tranferred from the acid to the base. Why is this so? Does this have something to do with water having a unique property?
 
You are still ignoring fact that NaOH is fully dissociated. There is no such thing as NaOH in solution, so it can't react.
 
Oh ya, I completely forgot about that. Thank you. However I do have another question on how if NH3 and HCl reacted? Would the result be NH4+ and OH-? But if that is so, then it would mean that when an acid reacts with a base, a salt and water is not always the result. If so, when does this rule apply and when does a reaction between a base and an acid result in another acid and base?
 
DarylMBCP said:
how if NH3 and HCl reacted? Would the result be NH4+ and OH-?

Why OH-?
 
OH- because NH4+ gains a H+ ion since it is the base resulting in OH-. So are NH4+ and OH_ the products for such a reaction?
 
NH3 has a lone pair that can accommodate H+, that's right. However, where is the source of OH-? Please remember you are reacting NH3 with strong acid.
 
remember you are reacting NH3 with strong acid

Are you referring to H2O as the strong acid since it is left to react with NH3?
 
  • #10
DarylMBCP said:
Are you referring to H2O as the strong acid since it is left to react with NH3?

No, please take a look again at the original question you have posted.

DarylMBCP said:
how if NH3 and HCl reacted?

You listed two substances, one of them is a strong, mineral acid. One of the most common strong acids.
 
Last edited:
  • #11
Sorry about that. I forgot about my original question in mind. What I mean is, I do have question on how if NH3 and HCl reacted? Would the result be NH4+ and Cl-? But if that is so, then it would mean that when an acid reacts with a base, a salt and water is not always the result. If so, when does this rule apply and when does a reaction between a base and an acid result in another acid and base?
 
  • #12
DarylMBCP said:
What I mean is, I do have question on how if NH3 and HCl reacted? Would the result be NH4+ and Cl-?

Yes.

But if that is so, then it would mean that when an acid reacts with a base, a salt and water is not always the result. If so, when does this rule apply and when does a reaction between a base and an acid result in another acid and base?

Look for extended definitions of acids and bases. Classic one (Arrhenius) treats everything in terms of OH- and H+ - it fails for ammonia and HCl reaction. This one can be easily understood in terms of Brønsted-Lowry's acids and bases.
 
  • #13
Actually, I'm very new to the topics od Acids and Bases so I don't think I was able to understand everything on that webpage very clearly. Still, this is what I think it meant and how it applies to my question; Ammonia and HCl for NH4+ an Cl-. NH4+ is a conjugate acid and Cl- is a conjugate base. Am I right?
 
  • #14
No, conjugate acid and conjuage base differ just by one proton.
 
  • #15
So let me try to get what u are saying and from the hyperlink you attached; The reaction I stated above results in NH4+ and Cl- and both aren't a conjugate acid and base pair. That is because the base, NH3 does not contain OH-. Is that true?
 
  • #16
DarylMBCP said:
NH4+ and Cl- and both aren't a conjugate acid and base pair

My English fails me here and I am not sure what you mean (word 'both' make the statement unclear for me). IF you mean that NH4+ is not conjugate acid of Cl- and vice versa - then you are right.

That is because the base, NH3 does not contain OH-. Is that true?

It can be put this way, but it doesn't have to. You are all the time trying to use Arrhenius definition of base to ammonia - that's why you still have problems understanding the case.
 
  • #17
Borek said:
It can be put this way, but it doesn't have to. You are all the time trying to use Arrhenius definition of base to ammonia - that's why you still have problems understanding the case.

What is that other way or definition that my explanation can be put? Is it that a base is defined as any substance that can accept a hydrogen ion?
 
Last edited:
  • #19
Ok thank you very much for your help so far.
 

Similar threads

Chemistry How does Bronsted-Lowry definition of base apply to NaOH exactly?
  • · Replies 5 ·
Replies
5
Views
3K
Which formula to use to find the pH of a solution?
  • · Replies 20 ·
Replies
20
Views
3K
Redox Reaction in Dissolved Ammonium Chloride
  • · Replies 5 ·
Replies
5
Views
3K
How Much Energy Is Released When Mixing HCl and NaOH?
  • · Replies 1 ·
Replies
1
Views
2K
Chemistry How to take into account autoprotolysis in weak base solution?
  • · Replies 8 ·
Replies
8
Views
3K
Find ph based on given volume and molarity of HCl and NaOH
  • · Replies 22 ·
Replies
22
Views
7K
Chemistry Understanding Heat of Neutralization in Acid-Base Reactions
  • · Replies 9 ·
Replies
9
Views
3K
Can hydrogen be abstracted from urea?
  • · Replies 3 ·
Replies
3
Views
2K
Enthelpy of neutralization of HCl and NaOH
  • · Replies 3 ·
Replies
3
Views
13K
How Can Ammonia Be Used to Adjust the pH of a Highly Acidic Solution?
  • · Replies 11 ·
Replies
11
Views
4K