A STORY
ABOUT ZINC
One
of the best-known stories of zinc is in Primo Levi’s “The Periodic Table”, a
wonderful book of short stories based around Levi’s chemistry experiences
whilst studying for and during a career as an industrial chemist. This short
description cannot do justice to Levi’s beautiful writing, but hopefully
provides a flavour.
In
this short story about zinc, Levi has just graduated from being one of 80
university freshmen to having the status of being allowed into the Preparation
laboratory. This was his first exposure at university of being taken away from
books and written chemical studies and being initiated into the real art of
practical chemistry. Levi found this a rather brutal experience, since little
guidance was given by his professor, and students were left to learn from
bitter experience – it was “sink or swim” and, probably intentionally, only
those who persevered, survived. On his first day in the Preparation laboratory,
Levi was given the task of preparing the chemical zinc sulphate (ZnSO4).
On paper this was simple: attack a piece of zinc with diluted sulphuric acid
and then concentrate the solution and crystallize out the solid crystals. First
he re-learned the lesson about diluting sulphuric acid – the acid must be added
to the water, not the reverse, otherwise it is “prone to wild rages”. Next he learned a lesson about zinc that,
whilst zinc is in theory readily attacked by sulphuric acid, if it is very pure
nothing happens and the reaction is inhibited. Levi describes how “some salt
and mustard” are needed, in this case a few drops of copper sulphate, and then
the zinc will “wake up”.
Levi
describes zinc as an element that is grey and boring. Indeed, this is exactly what zinc is: a boring metal that, in the
right applications, does a beautiful job as an unsung hero. But Levi’s stories
in “The Periodic Table” go much further than describing his experiences in a
laboratory, weaving together interesting chemistry experiences with his story
about life and about people. In this particular story he builds a bridge
between himself and Rita, another student who, later that day he accompanies on
her walk back to her home, after leaving the results of his attempts to
crystallize his zinc sulphate to their own fate.