Answers to Firas

Hey Firas, don't apologize for your questions, this blog was made to answer your questions in the first place.
Q 1) The anode is the electrode that gets thinner since it loses electrons, so the atoms on the anode change into ions (from solid state (atoms) to aqueous state (ions))
On the other hand, the cathode is the electrode that gets thicker, since it gains electrons, so it attracts the cations of the metal from the solution, the cations will gain the electrons (be reduced) to become atoms (solids) which will stick on the cathode.
Q2) The word electrolyte doesn't mean catalyst. Electrolytes are substances that conduct electricity, in this case, they are the ions in the solution. We know that ions conduct electricity because they are charged particles.
Q3) A spontaneous reaction that proceeds on its own, while a non-spontaneous reaction cannot start by itself, it needs a form of energy to start. For example, decomposing water into hydrogen and oxygen gases requires either of these energies: heat (2000 C or an electric current). For this reason, decomposing water is a non-spontaneous reaction.
Q4) yes, for both types of electrolysis we use an electrolytic cell.
Remeber that an electrolytic cell is a cell the depends on a source of electricity (battery), it converts electric energy to a chemical energy.
Q5) yes, you can memorize it this way
Since the oxidant is the substance reduced, then for sure it is the substance whose O.N. decreased, and since the reductant is the substance oxidized, then for sure it is the substance whose O.N. inreased.
Q6) They can be memorized, since only 2 cases are required from you (electrolysis using KNO3 or H2SO4)