Explanation:

The value of
:
![K_w=[H^+][OH^-]](https://tex.z-dn.net/?f=K_w%3D%5BH%5E%2B%5D%5BOH%5E-%5D)
a. pOH = 3.51
The sum of pH and pOH is equal to 14.
pH + pOH = 14 (at 25°C)
pH = 14 - 3.51 = 10.49
The pH of the solution is defined as negative logarithm of hydrogen ion concentration in solution.
![pH=-\log[H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BH%5E%2B%5D)
![10.49=-\log[H^+]](https://tex.z-dn.net/?f=10.49%3D-%5Clog%5BH%5E%2B%5D)
![[H^+]=3.2\times 10^{-11}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D3.2%5Ctimes%2010%5E%7B-11%7D)
is the
concentration for an aqueous solution with pOH = 3.51 at 25°C.
b.
At a certain temperature, the pH of a neutral solution is 7.56.
Neutral solution means that concentration of hydrogen ion and hydroxide ions are equal.
![[H^+]=[OH^-]](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BOH%5E-%5D)
![7.56=-\log[H^+]](https://tex.z-dn.net/?f=7.56%3D-%5Clog%5BH%5E%2B%5D)
![[H^+]=2.754\times 10^{-8} M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D2.754%5Ctimes%2010%5E%7B-8%7D%20M)
The value of
at at this temperature:
![K_w=[H^+][OH^-]](https://tex.z-dn.net/?f=K_w%3D%5BH%5E%2B%5D%5BOH%5E-%5D)
![K_w=[H^+][H^+]](https://tex.z-dn.net/?f=K_w%3D%5BH%5E%2B%5D%5BH%5E%2B%5D)

The value of
at at this temperature is
.
Answer:
The electrochemical phenomenon of rusting of iron can be described as : At Anode: Fe (s) undergoes oxidation to releases electrons. Electrons released at anode move to another metal and reduce oxygen in presence of H+. It is available from H2CO3 formed from the dissolution of CO2 from air into water.
Stirring and agitating chemical reactions is desirable and stirring reflux systems or any system under heating is necessary to a distribute the heat evenly throughout the system and b) to prevent splashing and boilovers.