Regarding the E(cell) values, how do we know if a reaction can occur or not? For example: mj02, q4(c): (i)no reaction occurs, well how can we decide so? and (ii) a reaction occurs. Is there like a 'least value of an E(cell) of a reaction to occur'?. And also, can someone please explain which value we subtract from which in calculating this E(cell) value? I notice sometimes in every paper its different and I have found it really confusing.
Thanks in advance and I really appreciate the help.