ph/ strength of a chemical

[mollykins]

I thought that if you mix two chemicals of ph1 and ph7 the product would have a ph of about 3.5.

But in chemistry today, we made dilutions of hydrochloric acid and put universal indicator in and they all went redish, indicating a ph of about 1. Now if you're dilating it with water, it shouldn't matter how much water you put in, i would think that all the dilations would have gone yellow/ orange (all the same shade) and the one that had no water added would stay red, why didn't it?

[Pigletion]

pH is logarithmic, not linear, so each pH is ten times different to the next one, i.e. pH 1 is ten times as acidic as pH 2.


This might help http://www.elmhurst.e.../vchembook/184ph.html

As might this http://www.algebralab...x?file=Algebra_ph.xml as you can solve the problems and then check your answers.

[mollykins]

ahh i thought the amount of each liquid was irrelivant to the end ph, so if you have a very strong acid and only add a little h20, it won't affect it enough for a visiblr difference with universal indicator. i think i understand it now

[maelogman]

Bit late, but it might help. "Dilute" hydrochloric acid has a pH of around 0; diluted ten times will move it to around 1, a hundred times to about 2 and so on. You would need about a million times dilution to reach a pH where the indicator would begin to change at around pH 6