When we electroplate something with silver, we usually put silver as anode and the object going to be sticked on as the cathode.

Moreover, an aqueous silver solution is also preferred.

If we need to electoplate iron spoon with silver, we can't use silver nitrate solution. There's a direct reaction become the silver ions and iron atoms.

We ought to use silver cyanide as solution.

Can anyone figure out why this solution has the function of forbidding the reaction between the two ions?

This looks like an electro-chemical effect: In fact to electroplate with silver you use a low voltage of about 2 volts. This threshold may have a bearing on the collision complex through average velocity of regeants. Also, I would investigate the effect of inevitable impurities and oxidation byproducts whenever dealing with iron. I seem to recall 'balling' and skin effects with iron surfaces in a variety of situations.

I don't see why electroless nitrate wouldnt work. Just throw it all in a jar and shake like there is no tommarow. Wash. Repeat if needed.

It works but you don't get a good deposit. Once the surface iron is used up, plating stops. The silver potasium-cyanide bath puts on a nice hard level deposit at about 0.9V. Ideal for post-plate buffing.

also, just sticking it in a solution proces are layer that wil lprobalyjust fall of before you pull it out of the water. This is what happens to me when i tried plating this way with copper sulfate.

I have done it will silver hydroxide and acetate which is much worse than nitrate. It worked fine for me. Copper sulfate does not work very well for electroless plating though.