Chem兩題,,,急急急,,今日要啦!!! (10分)

(1)
Metals are commonly found in form of oxide. In order to purify them,
extraction is required. The removal of an oxide layer is a reduction step.
However, in those day, only very simple reducing agent such as carbon
can be found in the nature the chemist. As a result, only those metals able
to be reduced by carbon such as iron oxide, copper oxide, silver oxide,
impure gold can be extracted. Due to the above mentioned-reason, only not
very reactive metal oxides can be extracted.

For those quite reactive metals, (those in higher position of the reactivity
series),can only be extracted by electrolysis. However, in those times,
battery was not invented. Not until the end of 18 century, did the battery
invent. As a result, no electrolysis can't be carried out nor can extract
those reactive metals such as sodium, potassium and aluminum.

(2)
As the definition of displacement said: A metal in high reactivity
series, will displace any in lower reactivity series from the solution
of its salt. The best way to test the reactivity of a metal is to put
the iron and lead bar into the nickel(II)sulphate, to observe if there
is any displacement reaction to occur.

The assumption is as follows:
(a)If iron is more reactive than nickel, nickel metal will be displaced and
sinks to the bottom of the beaker due to its high density. The reaction is:
Ni 2+(aq) + Fe(s)→Fe2+(aq)+ Ni(s)
(b) If lead is more reactive than nickel, nickel metal will be displaced and
sinks to the bottom of the beaker due to its high density. The reaction is:
Ni 2+(aq) + Pb(s)→Pb2+(aq)+ Ni(s)

By observing which one of reactions will occur, we can conjecture which
metal is more reactive than Ni and the order of series can be constructed.
Since,we know than Fe is more reactive than Pb, if (a), the series should be:
Ni勁過Fe勁過Pb. If (b) Fe勁過Ni勁過Pb