Answer:
The strong acid reacts with the weak base in the buffer to form a weak acid, which produces few H+ ions in solution and therefore only a little change in pH.
Explanation:
When a strong acid is added to the buffer, the acid dissociates and furnish hydrogen ions which combine with the conjugate of the weak acid, forming weak acid. The weak acid dissociates to only some extent and can furnish only some protons and there is no significant change in the pH.
Hence, option B is correct.
Answer: The net ionic equation for the cobalt-silver voltaic cell is 
Explanation: In cobalt-silver voltaic cell, one half of the cell consists of cobalt electrode immersed in
solution ( which means that
are present in the solution) and other half of the cell consists of the Ag electrode immersed in
solution ( which means that
is present in the solution)
The two electrodes are joined by the copper wire. The cobalt electrode acts as an anode and the silver electrode acts a cathode.
At anode, oxidation reaction takes place and at cathode, reduction reaction takes place.
At Anode : 
At Cathode: ![[Ag^+(aq.)+e^-\rightarrow Ag(s)]\times 3](https://tex.z-dn.net/?f=%5BAg%5E%2B%28aq.%29%2Be%5E-%5Crightarrow%20Ag%28s%29%5D%5Ctimes%203)
Net ionic equation: 
Answer is (b)
2,3,1 is the stoichiometry
The values in front of the elements are the stoichiometric values
(Since Al2Br6 has no value in front, it's considered 1)
Answer:
a)22.2°C after adding magnesium
b)17.3°C before adding magnesium
c) 4.9 is change