Solution :
A cell that is concentrated is constructed by the same half reaction for the anode as well as he cathode.
We know,
In a standard cell,
the reduction half cell reaction is :
The oxidation half ell reaction :
Thus the complete reaction of the cell is :
cell = 
In a balloon there is a low pressure within the balloon. This means that the particles are more spaced out. Wheras in the cylinder they are under high pressure, meaning that the particles are much closer together!
Ionic bonds is formed between metal and nonmetal with opposite charges. Metal have (+) charge and nonmetals often have (-) charge.
Choice (a) is wrong because both charges are the same.
Choice (c) is wrong b/c same changes.
Si and O do not have charges for now. (d) is wrong.
Choice (b) is correct. Opposite charges and the ionic compound is BaCl2
