Acids And Bases Flashcards
(24 cards)
Natural indicators
Litmus paper, red cabbage extract, turmeric.
Synthetic indicators
Phenolphthalein, methyl orange.
Olfactory indicators
Vanilla extract, clove and onion (lose their smell in basic medium)
Red cabbage extract colour change
Red in acid and green in basic.
Turmeric colour change
Yellow in acid and red in base
Acids’ physical properties
- sour in taste
- turns blue litmus red
Organic acids
Formic, acetic, malic, citric, tartaric
Inorganic/Mineral acids
HCl, H2SO4, HNO3, HF, H2CO3, H2SO3
What are concentrated and dilute acids?
Conc. Acids - Acids which contain more H+ ions per unit volume. Dil. Acids are the opposite.
How to dilute acid/base?
By adding drop by drop solution to water with careful study. This is because adding water to solution is highly exothermic. This heat can only be absorbed by large volumes of water. Also, the thick viscous solution may break the surface tension and cause splash.
Reaction of acid with metal
Hydrogen + Salt
Reaction of acid with metal oxide
Water + Salt
What is the nature of metal oxides?
Since metal oxides react with acids to give salt and water, they are basic in nature.
Reaction of acid with metal carbonate and bicarbonate
Carbon dioxide + water + salt
What happens when excess carbon dioxide is passed through line water?
Milkiness is lost because calcium bicarbonate is formed, which soluble in water.
What is temporary hardness of water?
It is caused due to carbonates and bicarbonate of calcium. It can be removed by boiling.
CaCO3 forms
Limestone, chalk and marble
Reaction of acid with bases
‘Neutralisation’
Salt + water
Properties of bases
- bitter in taste and soapy to touch
- turns red litmus blue
- water soluble bases are alkali
- metal oxides also act as bases
- conduct electricity in solution
Reaction of bases with metals
Salt + H2 (but not all metals react with bases) (Only Zn, Sn and Al react)
Reaction of bases with non-metal oxides
Salt + H2O
Reaction of bases with acids
Salt + H2O
How are acids stored?
They are never metal containers as they can corrode. They are stored in glass bottles.
But HF cannot be stored in glass as HF reacts with silica (it is stored in wax coated glass or plastic)
What is basicity?
Number of replaceable H+ ions in an acid. Called so it indicates the number of bases it can neutralise.
