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6A.9 a

Posted: Sun Dec 01, 2019 5:13 pm
by Gabriella Bates 2L
Which of the following can be classified as reactions between Brønsted acids and bases? For those that can be so classified, identify
the acid and the base. (Hint: It might help to write the net ionic equations.) (a) NH4I(aq) + H2O(l) -> NH3(aq) + H3O1(aq) + I2(aq)

Would the acid in this case be NH4+ or NH4I? Thanks!

Re: 6A.9 a

Posted: Sun Dec 01, 2019 5:24 pm
by Harry Zhang 1B
The chemical equation is not balanced(The I2 should be just I^-(aq)). After correcting this, writing the net ionic equation, the I^- ions will cancel out and the species left are NH4+,H2O,H3O^+,NH3. Since the proton donator is NH4+, NH4+ is the bronsted acid.

Re: 6A.9 a

Posted: Sun Dec 01, 2019 10:24 pm
by DesireBrown1J
Harry Zhang 1D wrote:The chemical equation is not balanced(The I2 should be just I^-(aq)). After correcting this, writing the net ionic equation, the I^- ions will cancel out and the species left are NH4+,H2O,H3O^+,NH3. Since the proton donator is NH4+, NH4+ is the bronsted acid.


Why would it be NH4+ as the acid instead of NH4I? And how did you get NH4+ from this equation?

Re: 6A.9 a

Posted: Fri Dec 06, 2019 9:02 am
by Harry Zhang 1B
This is because NH4I will dissociate in water and the definition of a bronsted acid is a proton donor and NH4+, being a strong conjugate acid of a weak base NH3, will donate its proton to the water molecule. On the other hand, I- is the weak conjugate base of a strong acid HI and will not affect the pH level of water.