How do you complete and balance neutralization reactions in aqueous solution?

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Discussion Overview

The discussion revolves around completing and balancing neutralization reactions in aqueous solution, specifically focusing on the reaction between ammonia (NH3) and nitric acid (HNO3). Participants are tasked with providing molecular equations, net ionic equations, and understanding the underlying concepts of acid-base reactions.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that the reaction between NH3 and HNO3 produces ammonium nitrate (NH4NO3), while others express confusion about the correct representation of the reaction.
  • There is a discussion about the need to provide net ionic equations, with some participants emphasizing the importance of understanding what is being asked in the question.
  • One participant mentions that ammonia acts as a Bronsted-Lowry base, accepting a proton (H+) to form NH4+, while NO3- is considered a spectator ion.
  • Several participants discuss the Arrhenius and Bronsted-Lowry theories of acids and bases, questioning how these theories apply to the reaction in question.
  • There is a mention of typographical errors in the representation of the ionic equations, leading to further clarification attempts.
  • One participant expresses difficulty in understanding how to derive the molecular formula from the ionic equation, indicating a lack of clarity in the textbook's explanation.
  • Another participant suggests that acids react with bases to produce salts, prompting a discussion on identifying the acid, base, and resulting salt in the reaction.
  • There is a mention of a different reaction involving aluminum hydroxide and nitric acid, with participants discussing the stoichiometry involved in that reaction.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to balance the equations or the correct representation of the reactions. Multiple competing views on the application of acid-base theories and the correct ionic and molecular formulas remain unresolved.

Contextual Notes

Some participants note that the textbook may not clearly explain the process of deriving molecular formulas from ionic equations, leading to confusion. There are also references to typographical errors that may affect the clarity of the discussion.

Who May Find This Useful

This discussion may be useful for students learning about acid-base reactions, particularly those struggling with the concepts of neutralization, ionic equations, and the application of different acid-base theories.

BrainMan
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(Question) Complete and balance each of the following molecular equations (in aqueous solution); include phase labels. Then, for each, write the net ionic equation.

(A) NH3 + HNO3 ->

(Attempt) I thought that the acid HNO3 would just give it's hydrogen to NH3 and make the resulting reaction NH3 + HNO3 -> HNH3 + NO3. However the correct answer is NH3 + HNO3 -> NH4NO3.
 
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BrainMan said:
(Question) Complete and balance each of the following molecular equations (in aqueous solution); include phase labels. Then, for each, write the net ionic equation.

(A) NH3 + HNO3 ->

(Attempt) I thought that the acid HNO3 would just give it's hydrogen to NH3 and make the resulting reaction NH3 + HNO3 -> HNH3 + NO3. However the correct answer is NH3 + HNO3 -> NH4NO3.

Your answer appears to me an answer to the second question on the right lines except you seem to have forgotten they asked for the net ionic equation. So if you answer that more carefully that's what what actually happens, is, then this ionic mixture is called ammonium nitrate formally written with the the book answer. I.e you have to represent it as what they thought it was maybe 150 years ago.

It's understanding not so much chemistry as what the questioners want and if you can't grasp this IMHO lose an odd point and live with it. :biggrin:
 
epenguin said:
Your answer appears to me an answer to the second question on the right lines except you seem to have forgotten they asked for the net ionic equation. So if you answer that more carefully that's what what actually happens, is, then this ionic mixture is called ammonium nitrate formally written with the the book answer. I.e you have to represent it as what they thought it was maybe 150 years ago.
It's understanding not so much chemistry as what the questioners want and if you can't grasp this IMHO lose an odd point and live with it. :biggrin:
I answered the first part which was to complete the molecular formula. I don't get your explanation.
 
Ammonium nitrate is very soluble. You would expect to be able to represent the reaction:


NH3+HNO3 ---------->HNH+4 + NO-3
 
Last edited:
BrainMan said:
(Question) Complete and balance each of the following molecular equations (in aqueous solution); include phase labels. Then, for each, write the net ionic equation.

(A) NH3 + HNO3 ->

(Attempt) I thought that the acid HNO3 would just give it's hydrogen to NH3 and make the resulting reaction NH3 + HNO3 -> HNH3 + NO3. However the correct answer is NH3 + HNO3 -> NH4NO3.


symbolipoint said:
Ammonium nitrate is very soluble. You would expect to be able to represent the reaction:


NH3+HNO3 ---------->HNH+4 + NO-3
BrainMan said:
I answered the first part which was to complete the molecular formula. I don't get your explanation.

You were asked for an ionic equation but there are no ions in your equation. Symbolipoint has give an ionic equation but there is a typo.
It could hardly be simpler - between your two starting molecules a proton, H+ , is transferred.

In solution these ions are all there is. Even when it crystallizes the crystal is a lattice of these ions. It is called ammonium nitrate, think of what any other salt is called, and given the formula in your book. Which is what you will see on a bottle of the crystals like you will see common salt written NaCl and not Na+Cl- which is really what it is.

And then NaCl and NH4NO3 do represent the composition of the salts.

I just remembered the way related salts are described sometimes. Related to ammonia are amines and amino acids. In these one or more H of NH3 are substituted by organic groups. And you will easily see bottles labelled "glycine hyrdrochoride HOOCH2NH3.HCl" or the common buffer salt tris(hydroxymethyl)aminomethane) hydrochloride (HOCH2)3CNH2.HCl. Though I can't remember ever having seen straight ammonium salts described that way.

But this is no big problem, I'm sure you're ready now to re-read your textbook. :biggrin:
 
Last edited:
epenguin is right. I made a typographic mistake.

This, one digit different, is what should have been:


NH3 + HNO3 ---------> HNH3+ + NO3-
 
I know that this question asks for the ionic formula but my book actually wants you to find the molecular formula and then find the ionic formula. My problem is I don't understand how to do that with neutralization reactions. The books explanation on how to do this is terrible.
 
In terms of a simple Arrhenius theory of acids and bases neutralization reaction is

BOH + HA -> AB + H2O

(where BOH is a base and HA is an acid).

What to do with ammonia depends on whether you are taught only Arrhenius theory, or Bronwsted-Lowry theory as well.
 
Borek said:
In terms of a simple Arrhenius theory of acids and bases neutralization reaction is

BOH + HA -> AB + H2O

(where BOH is a base and HA is an acid).

What to do with ammonia depends on whether you are taught only Arrhenius theory, or Bronwsted-Lowry theory as well.

What does that have to do with this (A) NH3 + HNO3 -> ?
 
  • #10
Have you read the very last phrase of my post?

Which theory have you been taught?
 
  • #11
Borek said:
Have you read the very last phrase of my post?

Which theory have you been taught?
I have been teaching myself through a book and it mentions both theories.
 
  • #12
So it will be better to apply Bronsted-Lowry to ammonia, which is a proton acceptor (BL base):

NH3 + H+ -> NH4+

That's net ionic for the ammonia. NO3- is just a spectator (as nitric acid is considered to be strong and always fully dissociated).
 
  • #13
Borek said:
So it will be better to apply Bronsted-Lowry to ammonia, which is a proton acceptor (BL base):

NH3 + H+ -> NH4+

That's net ionic for the ammonia. NO3- is just a spectator (as nitric acid is considered to be strong and always fully dissociated).

OK I understand how to get the ionic formula but how do I get the literal formula with the spectators included. So how do I find the formula before I convert it to the ionic formula? The question in the book only included one side of the equation (A) NH3 + HNO3 -> and left the other side blank. How do I first find what's on the other side?
 
  • #14
Many ways of skinning that cat.

For example: acids react with bases producing salts. What is the acid here, what is the base here, what is the salt that combines them?

Another approach is to go net ionic first, molecular later. HNO3 is 100% dissociated. What do you have in the solution? What reaction do you expect? What ions will be present in the solution? How can you combine them to produce a salt?
 
  • #15
Borek said:
Many ways of skinning that cat.

For example: acids react with bases producing salts. What is the acid here, what is the base here, what is the salt that combines them?

Another approach is to go net ionic first, molecular later. HNO3 is 100% dissociated. What do you have in the solution? What reaction do you expect? What ions will be present in the solution? How can you combine them to produce a salt?

OK then how do I do start this problem (a) the reaction of solid aluminum hydroxide with nitric acid. So I wrote that out in equation form and got AlOH + HNO3 -> and I figured that you would produce AlNO3 + H2O. Turns out the correct answer is Al(NO3)3 + 3H2O. Where did the extra subscript 3 come in?
 
  • #16
Aluminum will react with water to form a hydroxide. However it will react with water in a way in which the net charge is 0. Being on group 13, you know that aluminum will form an ion with a 3+ charge. Hydroxide on the other hand, is an ion with a -1 charge. In order to find the ratio in which the two ions combine, you must find the least common denominator, being 3, and dividing 3 by the two charges to find the respective ratios. So you will end up with Al1(OH)3.
 
  • #17
Teemo said:
Aluminum will react with water to form a hydroxide. However it will react with water in a way in which the net charge is 0. Being on group 13, you know that aluminum will form an ion with a 3+ charge. Hydroxide on the other hand, is an ion with a -1 charge. In order to find the ratio in which the two ions combine, you must find the least common denominator, being 3, and dividing 3 by the two charges to find the respective ratios. So you will end up with Al1(OH)3.

Yeah I just realized that. OK so I think that I have gotten the first step now I am having trouble with the ionic equation. So the equation is 2HCN + Ca(OH)2 -> Ca(CN)2 + 2H2O. So I separated all all the ions except water and canceled out the rest. So I got H+ + OH- -> H2O. The correct answer is HCN + OH- -> H2O +CN-
 
  • #18
BrainMan said:
So I got H+ + OH- -> H2O.

Quite good - that's the essence of most of the neutralization reactions. However, it requires acid and base to be strong enough to be already dissociated. HCN is a very weak acid, and is dissociated in very small degree, so the solution is dominated by the HCN molecules, hence

The correct answer is HCN + OH- -> H2O +CN-
 

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