You can use a different reference electrode (Hg/Hg2SO4 for example), your Ag/AgCl electrode with a salt bridge filled with your test solution so that the precipitation process will occur only in the salt bridge, OR just a silver wire as pseudo-reference electrode.

I mixed a drop of KCl with Ag deposition solution and the same white matter appeared,meaning that my reference electrode undergoes leaching of the KCl solution into the deposition solution. 

If this is really so, are there any solutions or alternative options?

You can use a different reference electrode (Hg/Hg2SO4 for example), your Ag/AgCl electrode with a salt bridge filled with your test solution so that the precipitation process will occur only in the salt bridge, OR just a silver wire as pseudo-reference electrode.

AgCl is very readily formed when you have Ag+ and Cl- ions in solution, so it would probably be best to use a different type of reference electrode that does not contain Cl- ions (MSE, H2, etc.). If that is not possible, you can attempt to minimise the effect by using a Luggin capillary on your reference electrode, which would take your reference further away from the AgNO3 solution and slow down the mixing of your chloride and silver ions. In said Luggin you would put your electrolyte solution, but without the silver salt (so just H3BO3 + HNO3).

Thank you Romon and Daniela.

The idea of using Luggin capillary sounds the easiest but if I fill it with electrolyte, won't the electrolyte flow out into the Ag deposition solution? Because the Luggin Capillary which I have is a kind of simple bent capillary which does not contain any plugs to retain the electrolyte within it.

Hi Safdar,

One more option to consider: replace the fill solution of your Ag/AgCl reference electrode (if possible...most of the time it is) and probably replace the frit.  This will shift the reference potential slightly but you will still have the stability of the Ag/AgCl couple on the wire.  You can simply use the same electrolyte as your working solution.  This is commonly done to convert Ag/AgCl references for use with organic solvent.  With respect to the frit you may not need to replace it if you can soak out any residual chloride, but that can be time consuming.

Hi Safdar,

I think you have already good answer using Luggin capillary filled by NaNO3 as electrolyte , just checked the junction potential which will be thereabout the same.

...I should probably clarify: it's not an ideal solution.  It's a quick solution that works well enough for most people.  If you are running tests that will last for days, you probably want to get a chloride free reference electrode.

Cheers

Thank you Jacob for another useful suggestion.

I would first try the Luggin Capillary as suggested by Daniela. 

Jacob, my experiment lasts for about an hour because I am trying to deposit a Ag coating.

Hamdani, I am confused now. Should I use NaNO3 or my own electrolyte (H3BO3 + HNO3 filled .Luggin capillary? I am using a solution of AgNO3 + H3BO3 + HNO3 for Ag deposition

pardon H3BO3 + HNO3 

I agree that Luggin's work, but I would be concerned about an open tipped Luggin, with a different fill solution.  Depending on cell geometry you could be changing the effective mass transport of your desired (Ag+) to the WE surface.  You could use a bridge tube (not a true salt bridge, but effectively the same) which can serve the same function but are terminated with a frit, which would help with that transition.

Hello,

You can put ammonium nitrate in the Luggin probe+if necessary an intermediate salt bridge filled with saturated KCl;as you work in acid medium,ammonium cation will not interfere with silver

I have tried using Luggin Capillary but the reference electrode is large/long and does not tightly fit into the Luggin capillary.  :(

A quick solution to your experimental issue:

a) Take a piece of flexible silicone tube (long enough and as thin as possible)

b) fill up the tube with filter paper.

c) gently soak the filter paper with your solution.

d) connect one end of the tube to your reference electrode (just push the electrode slightly inside the tube) and submerge the other end in the solution. Be aware of air bubbles and/or electrolyte discontinuities.

Your reference is ready to work, with the AgCl precipitate entrapped in the filter paper.

Ag/AgCl reference electrode made it constant potential by Cl ion exchange through its ion permeable membrane. As Cl ions comes out of electrode through ion permeable membrane to AgNO3 solution it forms AgCl white coloured precipitate.

use salt bridge

If u want to use salt bridge use it with KNO3 electrolyte.

Good suggestion by Shivaji ( transport numbers  are  the same  -)

I tried the suggestion given by X. Ramón Nóvoa , and I noticed that it worked. But another issue appeared, that soon I pour AgNO3 deposition solution into the cell, Ag deposition starts in the form of islands on the WE. Then I apply voltage and dard precipitation starts to occur at the Pt counter electrode. Ag deposition seems to be a nasty phenomena. 

dear

Your bath pH is the culprit - vary bath pH - what is your WE?

from the Greek period Electro deposition of Ag is known

Dear Safdar,

You can never use an Ag/AgCl electrode in directly contact with an Ag+ solution, since your electrode is filled with Cl- solution. They precipitate! You are lucky that your junction was not obstructed in the contact. As some people have written, you must use a salt bridge with a non-reactive salt between your electrode and your solution. Since I don't know your system well enough I don't know what kind of salt bridge you should use, but you must use one. Maybe an agar salt bridge - a tube filled with agar prepared with KNO3 or NaNO3 solution - would suffice.

Regards

as suggested by X. Ramón Nóvoa,

use Hg/Hg2SO4 electrode instead of Ag/AgCl   OR

Use a pure silver wire as a reference electrode. Should work

it is silver chloride which is insoluble in nitric acid

Solution has Ag. The reference electrode Ag/Agcl in KCl solution. You will have leakage of cl- which reacts with ag+ to give you white insoluble agcl. You may want to look at other reference electrodes 

congrats Arun