All alkalis produce hydroxide ions when dissolved in water. How do we write the chemical equation for aqueous ammonia?
I see some textbooks write it as ammonia gas dissolving in water to form ammonium ions and hydroxide ions.

NH3(g)+ H2O(l) ==> NH4+(aq) + OH-(aq)

  1. 👍 0
  2. 👎 0
  3. 👁 114
asked by janice
  1. What you see in those text books is correct. I don't know if your confusion stems from the older definition of NH3 or not but here it is for what it's worth. In the older days (when I was in school), it was thought that NH3 gas dissolved in water to form NH4OH as follows:
    NH3 + HOH ==> NH4OH.
    Then, NH4OH ionized (partially since it is a weak base) to form the following:
    NH4OH <==> NH4^+ + OH^- and we went with that thought for many many years. It has been shown, however, (and I don't know the exact date but I think it was sometime in the 1960s or 1970s) that NH4OH does NOT exist. Therefore, ammonia may be described as a base by both the modified Arrhenius definition as well as the Bronsted-Lowry theory.
    By the modified Arrhenius we say a substance is a base if it produces OH- in solution. NH3 does this by
    NH3 + HOH ==> NH4^+ + OH^-.
    By the Bronsted-Lowry theory, a base is a proton acceptor. NH3, remember, has a pair of unshared electrons, shown here as :NH3 + HOH ==> NH4^+ + OH^-. Note that the :NH3 has accepted a proton (from water); thus, NH3 is a base and water is an acid. The reaction forms a conjugate acid (NH4^+) and a conjugate base (OH^-). I still see some reference now and then about NH4OH and it's ionization into NH4^+ and OH^- but the part about the existence of NH4OH is not true.

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    Sodium flouride, NaF, is a basic salt. Write the chemical equation that describes how the salt breaks up into its ions. Write the chemical equation that describes how one of the ions behaves as a base in water to produce OH-.

    asked by John on June 27, 2010
  2. Chem

    A solution containing hydroxide ions will react with chlorine gas to produce chloride ions, gaseous oxygen, and water. Cl2(g) + 2e- → 2Cl-(aq) O2(g) + 2H2O(l) + 4e- → 4OH-(aq) Write a balanced net ionic equation for this

    asked by Rose on June 14, 2018
  3. chemistry, science

    Carbon is also removed from the atmosphere during the process of weathering. carbon dioxide combines with water to form carbonic acid. this reacts with calcium silicate (in rocks) to produce calcium ions, bicarbonate ions and

    asked by Sophie on November 2, 2009
  4. Science

    When sodiun is placed in water,it reacts violent to produce hydrogen gas and form sodium hydroxide solution. write a balanced chemical equation for this reaction

    asked by Boren on February 10, 2017
  5. Physical Science

    How do you write the chemical equation for neutralization of nitric acid, HNO3, with magnesium hydroxide, Mg (OH)2, first with spectator ions and then without spectator ions?

    asked by Holly on February 20, 2012
  6. Integrated Science

    What is the difference between a weak and strong base? A).Only some of the molecules of a weak base dissociate to produce hydroxide ions when mixed with water, but all of the molecules of a strong base dissociate to produce

    asked by Kiley on December 15, 2018
  7. Chemistry

    2. The reaction can be described in words as follows: aluminum sulfate reacted with ammonium hydroxide forming the insoluble product or precipitate, aluminum hydroxide and the water-soluble ammonium sulfate. The chemical equation

    asked by Jerry on June 24, 2018
  8. chemistry

    1. Acids are substances that produce hydrogen ions (H+) when dissolved in water. Lemon juice is an example of an acid. A.What does lemon juice taste like? B.What does it feel like if lemon juice gets in your eye? 2. Bases are

    asked by Meep on May 6, 2019
  9. Integrated Science

    What do positive hydrogen ions produce when they react with water in solution? A).hydroxide ions B).hydronium ions C).a salt D).negative hydrogen ions I believe the answer is A). Is this correct?

    asked by Kiley on December 15, 2018
  10. Chemistry

    NH3 + Pb(NO3)2 -> How can I find the product and the net ionic equation? I suspect this is in a water solution, so the lead nitrate is in solution, but NH3 will react with the water to form ammonium ions, and hydroxide ions. The

    asked by Anonymous on October 21, 2006

More Similar Questions