Acids and Bases

SNC2D

Some Properties of Acids

Sour taste Water soluble Very reactive Conduct electricity Can act as a catalyst Corrosive Increase the hydrogen ion (H1+)

concentration of a solution Low pH (see chapter 7.3 The pH Scale)

Binary Acids

HX (where X is typically a halogen)

HX is typically a gas (HX(g)) e.g. hydrogen chloride (HCl(g))

When dissolved in water they form an acid e.g. hydrochloric acid (HCl(aq))

Oxyacids and Organic Acids

Oxyacids are acids where hydrogen is attached to a polyatomic ion that contains oxygen e.g. phosphate (PO4

3-) would give us phosphoric acid (H3PO4)

Organic acids are those found in nature and contain carbon e.g. vinegar (acetic acid) and ascorbic acid

(vitamin C)

Some Properties of Bases

Bitter taste Water soluble Very reactive Conduct electricity Caustic Are also described as alkaline Increase the hydroxide ion (OH1-)

concentration of a solution High pH (see chapter 7.3 The pH Scale)

Typical Bases

Bases usually contain the hydroxide ion (OH1-) e.g. sodium hydroxide (NaOH)

Some are more difficult to recognize bicarbonate (HCO3

1-) looks like an acid but can act as a base by taking a hydrogen ion from water and leaving behind the hydroxide ion

HCO31- + H2O H2CO3 + OH1-

Indicators Indicators are compounds that change colour to

identify an acid or base. Litmus red = acid

blue = base

Wide range pH

Phenolphthalein

Bromthymol Blue

Neutralization Reactions

acid + base salt + water

HCl + NaOH NaCl + H2O

HNO3 + KOH KNO3 + H2O

Credits http://commons.wikimedia.org/wiki/File:Hydrochloric_acid_ammonia.jpg