[plt-scheme] real but not rational?

Is it possible to (read) a value in PLT Scheme to get a value v such
that (real? v) is true and (rational? v) is false? I suppse that with
arbitrary precision arithmetic, this shouldn't be too surprising, but I
was surprised to see that my evaluator always tags numeric values as
rational, even values like 2.7e8 or 3.14159. I eventually plan to write
my own reader, but for now, I'm just using the underlying Scheme.

Irrelevant newbie question; What is the correct pronunciation of
MzScheme? I kind of assumed that DrScheme was "Doctor Scheme", MrEd was
"Mister Ed", etc. (but have been corrected on that point). I usually
end up saying M-Z Scheme, but wondered if it should be "Miz Scheme" (as
in "Les Mis", a colloquial reference to the musical.)

===
Gregory Woodhouse  <gregory.woodhouse at sbcglobal.net>
"All truth passes through three stages: First, it is ridiculed.
Second, it is violently opposed. Third, it is accepted as
being self-evident."
--Arthur Schopenhauer