Acids and Alkalis - Notes

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Acids:

There are both acids used in labs and natural acids in your stomach. Like vinegar and fruit acid. (can measure pH with UNIVERSAL INDICATOR, contains mixture of dyes. It goes a different colour depending on pH)

Acids dissolved in lots of water are called diulte acids

The more concentrated an acid = the less water it is dissolved in.

All acids contain hydrogen. In water this becomes active and causes the acid effect. When an acid reacts with a metal, the hydrogen is given off and salt is formed.

Acids that release lots of hydrogen and dissolve metals quickly are STRONG ACIDS

Those that release hydrogen slowly are WEAK ACIDS.

Bases:

Bases:

Bases are 'chemical opposites' of acids. They are COMPOUNDS which react with acids and neutralize them (cancel out acid effect).

Bases which dissolve in water are called alkalis. Alkalis are basically souble bases.

Alkalis can be just as corrosive as acids. Their powerful chemical action is often used in bath, sink and over cleaners

Strong acids: Weak Acids

Hydrochlric acid Ethanoic acid

Sulphuric acid Citric acid

nitric acid Carbonic acid

Properties of acids (in solution)

They have a sour taste (like vinegar)

Turn litmus red

React with most metals

React with most carbonates

Have a pH numbers less than 7

Strong Alkalis Weak Alkali

Sodium hydroxide Ammonia

Potassium hydroxide

Calcium Hydroxide

Properties of alkalis (in solution)

Feel soapy

Turn litmus blue

React with acids and neutralize them

Have a pH numbers greater than 7

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