synthesis 4-nitro aniline from 4-nitro acetanilide

I bet this is a lab report and so he needs an explanation of the mistake, not alternate path. And this reaction is usually done using acid (personally prefer HCl, it's less aggressive).

Could adding the wrong solution at any point explain this OP?

No, adding water to a strongly acidic solution will not change the pH much.

I don't mean to be insulting here, but the chemistry of a simple acetylysis is more dependable than any human being's recollection of what they did, especially when you ran the same reaction twice and got different results.

Here is an important factor, often when adding base to strong acid, people will check the pH before it is truly mixed, and get incorrect answers from their pH strips. I've done this several times by mistake. The strip will say it's basic becuase that top layer was basic, but really the full solution is still quite acidic when fully homogenized.

Also, don't you check your product by FTIR?

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Also, don't you check your product by FTIR?

No, I just wanted to understand what has happened before spectroscopic analysis (because of limited
facilities).
on the other hand I had to heat my reaction mixture with a lab mantel, and may be my Unrepeatable results is due to using that non standard mantel 

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I bet this is a lab report and so he needs an explanation of the mistake, not alternate path. And this reaction is usually done using acid (personally prefer HCl, it's less aggressive).

Could adding the wrong solution at any point explain this OP?

yes my explanation for the procedure is a lab report, I'm sure that I didn't add any wrong solution, is it possible that when I add water to reaction solution the mixture pH increases and the 4-nitro aniline participation occurs?

you could probably make 4-nitroaniline by hearing 4-nitroacetonilide with methanolic KOH. then precipitate with water.