I canot understand the ph value can anybody explain me that in details... I read about this theme but I can't understand...
thanks in advance

Have you tried Wikipedia? Excellent writeup.

No I don't but I will look thanks for help

PH is a way of writing down the concentration of hydrogen ions in a solution using a inverse logarithmic, this means that a decrease in a pH unit say pH3 to pH2 equals a tenfold increase in the number of hydrogen ions. There is loads of weird maths stuff you can get into but I have found this definition is all I have ever needed. What level of study are you at?

thanks a lot Templelane for your help... now I understand very good and very clearly ph value thanks again... I am in third year of high school...

Yeah the wiki entry was a bit too much - even I don't understand all the maths. I might be wrong but you probably don't even have to worry about how to work out pH yet, I didn't get that until 5th year. Even if you do just learn the equations they give you and it's an easy way to pick up marks in the exams. Good luck :)