mistake in solutions manual for 16.42(a)

[robert zellmer]

There is a mistake in the solutions manual's answer to 16.42(a) in the 
13th and 14th ed.

The question is a T/F question, "All strong bases are salts of the 
hydroxide ion".
The answer in the solutions manual is True.  That is not correct.

As stated in Section 16.5 on strong bases, the most common strong bases 
are the hydroxides
of group 1A metals and the heavier group 2A metals, Ca(OH)2, Sr(OH)2 and 
Ba(OH)2.
Mg(OH)2 is considered a "strong base" (strong electrolyte) since 
whatever part of it which
dissolves dissociates completely.  However, since it's not very soluble 
(and we'll see later
the Mg^2+ ion is slightly acidic) it's not usually included with the 
other group 2A bases.

It then goes on to state at the end of that section strongly basic 
solutions are also created by
certain substances which react with water to form OH- and gives the 
example of O^2-,
the oxide ion.  This is the conjugate base of OH-, if OH- acted as an 
acid, which it doesn't.
OH- the strongest base which can exist in water.  Thus the conjugate 
base of OH-, assuming
it acted as an acid, O^2-, is a stronger base than OH-.

There were several others I mentioned in class.  It's also discussed in 
the following two
links at the "Helpful Tidbits" link.  I also list some other examples of 
unusual strong bases
in the first link.

*Some Aspects about Acids and Bases* 
<https://cbc-wb01x.chemistry.ohio-state.edu/%7Erzellmer/chem1220/faq/acid_base.txt>

*Further Discussion on Acids and Bases* 
<https://cbc-wb01x.chemistry.ohio-state.edu/%7Erzellmer/chem1220/faq/amphoterism.txt>


Dr. Zellmer
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