about chemical cells problem

1.
potassium ion dissolves in all solutions
nitrate ion dissolves in all solutions
so potassium nitrate dissolves in all solutions
this can prevent precipitates form when salt bridge soaked in the electrolytes
some chloride such as silver chloride is insoluble
if we put the chloride salt bridge in a solution contain silver ion
precipitates form
2.
it will occur when the condition is favorable
that is, when there is a pair of metals with difference in reactivity
a more reactive metal will displace a less reactive metal from its solution
so if you immerse a more reactive metal into a less reactive metal ion electrolyte
displacement reaction occurs
3.
this is metal sulphite
it's because it is a reducing agent and it will undergo oxidation to sulphate
H2O + SO32- → SO42- + 2H+ + 2e-
so we need to prevent it from being oxidized
in the chemical cell
the negative electrode will undergo oxidation
if we use metal sulphite solution as the electrolyte of negative electrode
the sulphite maybe oxidizes instead of the metal negative electrode

1. potassium nitrate is chemically inert . It will not react with the reactants.
metal chloride such as sodium chloride can also be used .
sodium chloride is a stable compound .


2.displacement reaction will occur when a reactive metal put into a solution of less reactive metal. It can occur daniell cell or two half cells when the condition is flavourable.


3.nitrite ions are unstable .

It is a reducing agent.

SO3 2- ------> SO4 2-

It will react with the reactants in the chemical cell .

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