Untitled - Kelly Walsh High School

58 CHEMISTRY FOR THE UTTERLY CONFUSED
Don’t Forget!
TABLE 4-1 Abbreviated Activity Series of Metals*
Li(s) l Li (aq) e
Mg(s) l Mg 2 (aq) 2 e
Al(s) l Al 3 (aq) 3 e
Zn(s) l Zn 2 (aq) 2 e
Fe(s) l Fe 2 (aq) 2 e
Ni(s) l Ni 2 (aq) 2 e
H 2(g) l 2 H (aq) 2 e
Cu(s) l Cu 2 (aq) 2 e
*Refer to your text for a more extensive table.
Hydrochloric acid is a strong acid (strong electrolyte). Therefore, the species
present would be Mg(s), H (aq), and Cl (aq). Locate the element (Mg) and the
cation (H ) in the activity series.
Mg(s) l Mg 2 (aq) 2 e
H 2(g) l 2 H (aq) 2 e
In order for there to be a reaction between the two, the element must be above
the cation in the activity series. Since Mg is higher on the table, it will oxidize
(react as shown in the table). (Note: only Mg, not Mg 2 , undergoes oxidation.)
If a substance undergoes oxidation then something must also undergo reduction.
In this problem, the only option for a reduction species is the H . The
reduction is the reverse of the equation in the table.
The element in the activity series never has a charge.
4-5 Utterly Confused About
Net Ionic Equations
There are several ways to represent reactions in water. Suppose, for example,
that we were writing an equation to describe the mixing of a lead(II) nitrate
solution with a sodium sulfate solution and showing the resulting formation of