Ph And Indicators Flashcards
What is salt
A salt is a substance formed when H+ from an acid is replaced with metal or ammonium ( NH4+) ion
When H+ in HCl is replaced with sodium what salt is formed
NaCl ( sodium chloride )
When H+ in HCl is replaced with ammonium what salt is formed
NH4Cl ( ammonium chloride)
What is neutralisation
Neutralisation is the reaction between an acid and a base to form salt and water.
What is pH
pH = - log 10 (H+)
What are limitation of ph scale
Only has a range from 0- 14 , doesn’t work for concentrated solutions , only work for aqueous solutions
What is an acid base indicator
A substance that changes colour according to the ph of the solution in which it is placed
Methyl orange ph range
3 to 5
Methyl orange colour in acid and base
Acid = red , base = yellow
Litmus ph range
5 to 8
Litmus colour in acid and base
Acid= red , base= blue
Phenolphthalein ph range
8 to 10
Phenolphthalein colour in acid and base
Acid= colourless , base= pink
Formula for strong acid
Ph = - log 10 (H+ )
Formula for weak acid
Ph = - log 10 ( square root of ka into ma
Formula for strong base
pOH = - log10(OH-)
pH = 14 - pOH
Formula for weak base
pOH = - log10 ( square root of ka into mb )
pH = 14 - pOH
