pH & Indicators Flashcards
Limitations of the pH scale
Limited to 0-14 range, even though pH values outside this are possible
Doesn’t work with very concentrated solutions
Limited to aqueous soln.
Strong acid
HCl
Strong base
NaOH
KOH (potassium hydroxide)
Weak acid
Ethanoic acid
Weak base
NH3
To find the pH of a weak acid (ethanoic acid)
[H+]= (Ka x M(acid))
Phenolphthalein colour change
Colourless—> pink
Methyl orange colour change
Red—>yellow
Litmus colour change
Red—>blue
Acid—>base
Acid-base indicator
A substance that changes colour according to the pH of the soln. It’s placed in
Range of an indicator
The pH interval over which there’s a clear change in colour for that indicator
What is Kw
The ionic product of water [H+][OH-]
pH of a neutral soln. is 7 at…
25 degrees
The stronger the acid…
The weaker the conjugate base
The weaker the acid…
The stringer the conjugate base