Answer:
at the beginning:
pH = 0.745
Explanation:
HCl is a strong acid, so:
0.18 M 0.18 0.18.....equilibrium
before base is added:
∴ [ H3O+ ] ≅ <em>C </em>HCl = 0.18 M
⇒ pH = - Log [ H3O+ ] = - Log ( 0.18 )
⇒ pH = 0.745
Answer : 
is the oxidizing agent and Fe is the reducing agent.
Explanation :
Reducing agent : It is defined as the agent which helps the other substance to reduce and itself gets oxidized. Thus, it will undergo oxidation reaction.
Oxidizing agent : It is defined as the agent which helps the other substance to oxidize and itself gets reduced. Thus, it will undergo reduction reaction.
The balanced redox reaction is :
The half oxidation-reduction reactions are:
Oxidation reaction : 
Reduction reaction : 
In order to balance the electrons, we multiply the oxidation reaction by 4 and reduction reaction by 3 then added both equation, we get the balanced redox reaction.
Oxidation reaction : 
Reduction reaction : 
In this reaction, 
is the reducing agent that loses an electron to another chemical species in a redox chemical reaction and itself gets oxidized and 
is the oxidizing agent that gain an electron to another chemical species in a redox chemical reaction and itself gets reduced.
Thus, is the oxidizing agent and Fe is the reducing agent.
Explanation:
The solubility curve helps us to compare the solubility of difference substances at same temperature. It gives the idea that solubility changes with the temperature. The solubility curve helps us to predict which substance will crystalize out first from hot solution containing two or more solutes.
The pressure increase does not affect the equilibrium shift reaction.
