What's the problem ? Hardness is not the definition of a metal.
You need to expand your thinking. EVERY element is solid, liquid, and gas, over different ranges of temperature ... including all of the metals. There are only TWO elements that are liquid AT ROOM TEMPERATURE, and mercury is one of them. But on a mild day at the south pole, mercury is solid too.
Answer: Physical properties
Explanation: Can be measured without changing a substance's chemical identity.
Answer:
Approximately
, assuming that this acid is monoprotic.
Explanation:
Assume that this acid is monoprotic. Let
denote this acid.
.
Initial concentration of
without any dissociation:
.
After
of that was dissociated, the concentration of both
and
(conjugate base of this acid) would become:
.
Concentration of
in the solution after dissociation:
.
Let
,
, and
denote the concentration (in
or
) of the corresponding species at equilibrium. Calculate the acid dissociation constant
for
, under the assumption that this acid is monoprotic:
.