Acids and Bases 1

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Acids

Turn Litmus paper red

pH 0-6

reacts with metals to produce H2

e.g HCL HNO3 H2SO4, vinegar, lemon juice

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Bases

Turn litmus paper blue

pH 8-14

Neutralises acids

Called alkalis when dissolved in water

NaOH Na2CO3 NH3 CaCO3 Ca(OH)2

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Monobasic acid: Has only one removable hydrogen e.g HCl HNO3

Dibasic acid: two removable hydrogen's e.g H2SO4

Tribasic acid: three removable Hudrogens e.g Phosphoric Acid H3PO4

Acid + Base -----> Salt and Water HCl------> Chloride

HNO3 ----------> Nitrate

H2SO4 -----------> Sulphate

Acid + Metal---------> Salt + Hydrogen

Neutralisation: The reaction that occurs between an acid and a base to form Salt and Water

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Arrenius Definition of an Acid

Acid: A substance that dissociates in aqueous solution, forming hydrogen ions

Strong acids fully dissociate into their ions in water

Weak acids don't fully dissociate into their ions in water

Base: A substance that dissociates in aqueous solution to form hydroxide ions

Strong bases fully dissociate into their ions in water

Weak ions don't fully dissociate into their ions in water

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Bronsted-Lowry Theory

Acid: A proton donor Base: A proton acceptor

Amphoteric Substance: Can act as acid or base e.g Water

The definition applies to a broader range of substances and not just aqueous solutions

An acid changes into a conjugate base when it donates a proton

A base changes into a conjugate acid when it accepts a proton

A pair consists of an acid and a base that differ by a proton

The stronger the acid, the weaker the conjugate base (vice versa)

The stronger the base, the weaker the conjugate acid (vice versa)