Acids, Base and salts Flashcards
Acid
It is a substance that produces hydrogen ions when dissolved in water. The higher concentration of hydrogen ions in the solution the lower the PH.
Alkali
It is a substance that produces hydroxide ions when dissolved in water.
What happens to Acid in the water.
Acids completely ionise in water. They break up completely to produce a high concentration of hydrogen ions in the solution. For example, hydrochloric acid ionises completely into hydrogen and chloride ions.
What happens to Alkalis in the water.
Strong alkalis completely ionises in water. They break up to produce a high concentration of hydroxide ions in the solution. For example, sodium hydroxide ionises completely into sodium and hydroxide ions.
Weak acids
The weak acids only partially ionise in water. Only a small fraction of their molecules break into hydrogen ions when added to water.
Weak alkalis
The weak alkalis only partially ionise in water. Only a small fraction of their molecules break into hydroxide ions when added to water.
Concentrated Acid
It contains large number of acid particles dissolved per unit volume.
Dilute Acid
It contains a small number of acid particles dissolved per unit volume.
Neutralisation
It is the reaction between the hydrogen ions in an acid and the hydroxide ions in an alkali to produce water. The ionic equation for Neutralisation is Acid + Base = water.
What type of reaction is Neutralisation
It is a exothermic reaction, one which heat is given out. The maximum temperature is reached when the acid solution is completely neutralised by the alkali.
Base
A metal oxide or metal hydroxide that neutralises an acid to produce a salt and water. An alkali is a soluble base. All alkalis are bases, but only soluble bases are alkalis
Reactions of Acids
- If a gas is produced, the observations is bubbles
- If a solid such as a solid metal, base or carbonate reacts with the acid then the observation is solid disappears and a solution is produced.
- Most acid reactions are exothermic, therefore releasing heat.
Acid reactions with metal
Acids reacts with metal to produce a salt and hydrogen. Acid + metal → salt and hydrogen
Acid reactions with Base
Acid reacts with bases to form a salt and water. Acid + base → salt and water.
Acid reactions with carbonates and hydro carbonates
Acids react with metal carbonates and hydrogen carbonates in the same way. These reactions produce salt, water and carbon dioxide. Acid + carbonate → salt + water + carbon dioxide. Acid + hydrogen carbonate → salt + water + carbon dioxide
