The document discusses questions from a chemistry exam. One question asks to classify a reaction involving the complex ion [Cu(NH3)4]+. The summary is that this is a Lewis acid-base reaction, where Cu2+ acts as the Lewis acid by accepting an electron pair from the Lewis base NH3. Another question asks which half-reaction has the highest standard reduction potential. The summary states that the half-reaction with the highest potential is Br(aq) + 2e- → 2Br-(aq) + 1.09 V.

1. on of a complex ion such as [Cu(NH)l (aq) 1 categorized as a(n) reaction. " __ (A) Arrhenius
acid-base (B) Bronsted-Lowry acid-base (C) Lewis acid-base (D) oxidation-reduction 15. when
balancing this half-reaction in basic solution,-- electrons are added to the side of the equation.
MnO4 (aq) ? MnO2(aa) (A) 3. product (B) 3, reactant (C) 5, product (D) 5, reactant Which
reaction has Standard Reduction Potentials, V the highest potential under standard 16. Pb"(aq) +
2e ? Pb(s) -0.13 Sn"(aq) + 2e-? Sn2-(aq) +0.15 Br(aq) + 2e-2Br(aq) +1 09 conditions? (A) Sn
(aq)+ Pb(s) products (B) Br (ag)+ Sn (aq) products (C) Pb(s) + Br(aq) ? products (D) Pb (ag) Sn
(aq)-products
Solution
The answer for the 14th question is as follows:
A lewis acid is one that is an electron acceptor in a reaction. Also Cu +2
in the reaction is
positively charged and would readily accept electrons. So thinking of where does the electron
that Cu +2
gains come from?
The electrons come from the lone pair on NH 3 .
Thus, we have a electron donor and an electron acceptor. Also, you can call Cu +2
and
electrophile(lacking or deficient in electrons).
Thus we see that the copper ion is the lewis acid in the reaction as it accepts the lone pair of
electrons from NH 3 Thus ammonia acts as the lewis base as it donates it's electrons. Thus, this
reaction is an example of a lewis acid-base reaction.
Hence, option C is correct.