1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Bronsted - Lowry Theory Of Acids and Bases

  1. Feb 1, 2009 #1
    1. The problem statement, all variables and given/known data

    Some of the books I have state that the equation of....

    HCl + NH3 --> NH4+ + Cl-

    While others state that the above equation should be written as....

    HCl + NH3 --> NH4Cl

    Which one is correct? I think the answer should be the second one since the two compounds would want to reach its stable form by bonding. Am I right?
     
  2. jcsd
  3. Feb 1, 2009 #2

    Borek

    User Avatar

    Staff: Mentor

    In water or in the gas phase?
     
  4. Feb 2, 2009 #3
    What do you mean? Does the products of the reaction stated above depend on their state of matter? Please elaborate.
     
  5. Feb 2, 2009 #4

    Borek

    User Avatar

    Staff: Mentor

    In the gas phase product will be solid substance, in water - dissolved ions. Note, that solid made in the gas phase - once dissolved - will dissociate to exactly the same ions.
     
  6. Feb 4, 2009 #5
    When you say solid substance, are you talking about the NH4+ + Cl- or NH4Cl ? How about in other phases? Please elaborate.
     
  7. Feb 4, 2009 #6

    Borek

    User Avatar

    Staff: Mentor

    Sorry, I have no idea what you are asking about.

    Are you asking whether solid ammonium chloride is an ionic or covalent? I would expect mostly ionic.
     
  8. Feb 4, 2009 #7
    Lets put it another way by reference to a different compound -common salt.
    In the solid state the ions are strongly bound together and it is normal to use the formula NaCl.If now the solid is melted or dissolved the ions separate and we could write ,for each,Na+ and Cl-
    (how can I write + and - as superscripts?)
     
  9. Feb 4, 2009 #8

    Borek

    User Avatar

    Staff: Mentor

    With [ sup][ /sup] and [ sub][ /sub] tags. No spaces after opening bracket.
     
  10. Feb 4, 2009 #9
    Thank you Borek-I shall try it out.
     
  11. Feb 5, 2009 #10
    Sorry for not having phrased my question properly. Haha. I just want to know whether the product(s) of HCl + NH3 are either the two compounds, NH4+ + Cl-, or just one compound, NH4Cl. Are you saying that the product(s) of the reaction depends on its state?
     
  12. Feb 5, 2009 #11

    Borek

    User Avatar

    Staff: Mentor

    You may as well ask whether solid NaCl (kitchen salt) is one compound or two compounds.

    I have Canon EOS 400D with 28-105 mm USM lens. I can use the body with other lenses, I can use the lens with other bodies. Is it one compound, or two?
     
  13. Feb 5, 2009 #12

    epenguin

    User Avatar
    Homework Helper
    Gold Member

    When you are posting isn't there an X2 and an X2 little icon at the top of the answer screen, which people could use :mad:to make their posts more legible? :mad:
     
  14. Feb 5, 2009 #13

    Borek

    User Avatar

    Staff: Mentor

    Only if you use advanced interface, most people use quick reply.

    Which shouldn't stop them from the proper formatting.
     
  15. Feb 10, 2009 #14
    I have no idea what you are talking about because what are subsituting the body or the lens with? Please just go straight forward in answering my question because I need it to continue my progress. Thank you.
     
  16. Feb 10, 2009 #15

    Borek

    User Avatar

    Staff: Mentor

    Ionic salts are mixtures of (at least) two different ions. You have asked whether this mixture is one compound (salt), or two (two ions). This is wrong question. This is exactly the same case as with my camera, body and lenses being equivalents of different ions.

    Sorry, I have no idea how to explain it in different terms. Looks to me like tou are trying to deal with advanced concept (Bronsted theory), not understanding more basic concepts (ionic salts and dissociation). That's why you have problems.
     
  17. Feb 10, 2009 #16
    The two different equations are basically two different ways of saying the same thing.In the solid state,because of their close proximity the charges on the positive ions are balanced by the charges on the negative ions making an overall charge of zero and it is usual to leave out the + and -signs.When the ions are separated,for example by melting,
    it is usual to include the + and- signs.It is helpful to include the signs when explaining how the ions bond by electrical attraction but once the bonding is complete and the compound is formed it is normal to leave the signs out.One advantage is that it becomes more economical to write the equation.I have only a very basic knowledge of chemisry so if you are after an answer in terms of the Bronsted Lowry theorem then I dont know what this theory is although I am tempted to look it up.
     
    Last edited: Feb 10, 2009
  18. Feb 10, 2009 #17

    Borek

    User Avatar

    Staff: Mentor

  19. Feb 11, 2009 #18
    Oh I finally get what you mean because I have not been realising that Ammonium Chloride is salt. However, from what I have just understood, is it possible to say that generally an acid and a base forms a salt and sometimes water if the base is a metal hydroxide?
     
  20. Feb 11, 2009 #19

    Borek

    User Avatar

    Staff: Mentor

    Yes, acid and base reaction is one of the most basic methods of salt synthesis. And in inorganic chemistry water is almost always byproduct of this reaction, not sometimes.
     
  21. Feb 11, 2009 #20
    Just another quick example to check my understanding;

    Nitric acid and Ammonia forms Ammonium Nitrate

    where Ammonium Nitrate is a salt?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Bronsted - Lowry Theory Of Acids and Bases
Loading...