ShrikantLondhe Posted September 24, 2012 Report Share Posted September 24, 2012 (edited) In my chemistry practicals, I have an experiment using pH meter. I have to find the amount of strong acid given in a standard flask by titrating it with standard NaOH and recording the pH after every 1mL of added NaOH. Now, my problem is that when I take 10mL of the acid solution in a beaker and try to get the electrode apparatus (its a combined electrode) to dip into the solution, the level of the acid in the beaker is not enough to dip the hole leading to the electrode. So I am told to add some amount of distilled water in order to make up the level so as to dip the electrode in the acid solution. Now, if I am going to read the pH of the acid, why should addition of distilled water not change the pH at all? Edited September 24, 2012 by Shrikant Londhe Quote Link to comment Share on other sites More sharing options...
Turtle Posted September 24, 2012 Report Share Posted September 24, 2012 In my chemistry practicals, I have an experiment using pH meter. I have to find the amount of strong acid given in a standard flask by titrating it with standard NaOH and recording the pH after every 1mL of added NaOH. Now, my problem is that when I take 10mL of the acid solution in a beaker and try to get the electrode apparatus (its a combined electrode) to dip into the solution, the level of the acid in the beaker is not enough to dip the hole leading to the electrode. So I am told to add some amount of distilled water in order to make up the level so as to dip the electrode in the acid solution. Now, if I am going to read the pH of the acid, why should addition of distilled water not change the pH at all? because the "ideal" pH of distilled water is 7, i.e. neutral. What is the pH of distilled water?...Identification Distilled water ideally consists of only hydrogen and oxygen, with a completely neutral pH of 7. In reality, it almost always is slightly acidic, from 5.6 to just under 7, because the water absorbs carbon dioxide from the air. A gallon of distilled water can be made neutral by adding 1/8 tsp. of baking soda, a substance with a pH of 8.... then again, can't you measure the pH of the distilled water before you add it, and then infer the pH of the acid after measuring the acid + distilled water? :shrug: Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.