Answer: 
is a reactant; it is present before the reaction occurs.
Explanation:
In a chemical reaction the chemical formulas written before the arrow are described as reactants as they react together to form products which are written after the arrow.
Thus and HCl are reactants here whereas 
, 
and 
are products.
The correct answer would be A. The symbol Eo would represent the cell potential of an electrolytic cell. This potential is being created by two metals that possess different properties. The energy per charge that is available from the reaction of the metals is the measure of this potential and is related to the equilibrium constant, K.
Q1. TI (210/81Thallium)
Q2.
The answers are opposite from each other
where are the element you haven't showed it so that we can answer it
