Acids and Alkalis Flashcards
(23 cards)
what pH does the strongest acid have?
pH 0
what pH does the strongest alkali have?
pH 14
what pH does a neutral substance have?
pH 7
what pH is pure water?
pH 7
what is universal indicator?
a combination of dyes - to find the pH of an aqueous solution, add the indicator to the solution and compare the colour formed to a chart
what colour is methyl orange in acidic solutions?
red
what colour is methyl orange in neutral solutions?
yellow
what colour is methyl orange in alkaline solutions?
yellow
what colour is phenolphthalein in acidic solutions?
colourless
what colour is phenolphthalein in neutral solutions?
colourless
what colour is phenolphthalein in alkaline solutions?
pink
what colour is red litmus paper in acidic solutions?
red
what colour is red litmus paper in neutral solutions?
red
what colour is red litmus paper in alkaline solutions?
blue
what colour is blue litmus paper in acidic solutions?
red
what colour is blue litmus paper in neutral solutions?
blue
what colour is blue litmus paper in alkaline solutions?
blue
acid definition
H+ donor - have a pH of less than 7
base definition
H+ acceptor - can neutralise an acid
alkali definition
OH- donor - have a pH of more than 7
what is neutralisation?
the reaction between an acid and a base (or alkali)
what is neutralisation in terms of H+ and OH- ions?
H+ (aq) + OH- (aq) -> H2O (l)
what is neutralisation in terms of proton transfer?
- the acid donates protons which are then accepted by the base
- when an acid neutralises a base , the products are neutral
