Acids, Bases and Salts

Ms. MacInnes 2010Science 10

What do you think an acid is?

• Lactic acid (sore muscles & sour milk)

• Boric acid (antiseptic)

• Acetic acid (vinegar)

• Citric acid (citrus fruits)

• Hydrochloric acid (stomach acid)

Acids• an acid is a substance that produces

hydrogen ions in solution (H+)

Properties of acids• turns blue litmus paper red• turns bromothymol blue to yellow• sour taste• reacts with certain metals to produce H2

• Conducts electricity when dissolved in H2O• contains H+1 ions

Bases

What do you think a base is?

• a base is a compound that produces hydroxide ions (OH-) when in solution.

• Another term for “basic” is “alkaline”

• Examples:

• Antacids (Tums)

• Oven cleaner (Easy Off)

• Milk of magnesia

Properties of bases

• turns red litmus paper blue

• turns phenolphthalein pink

• bitter taste

• slippery feel

• conducts electricity when dissolved in H2O

• contains OH-1 ions (hydroxide)

Salts• An ionic compound which is produced

during a neutralisation reaction (reaction between acid & base)

Neutralisation• A chemical reaction where an acid and a

base combine to make a salt and water.

NaOH + HCl NaCl + H2O

Properties of salts

• Produced when an acid reacts with a base

• Has a solid crystalline structure

• Examples include table salt (NaCl), Epsom salt (bath), potassium chloride (KCl)

**not all compounds are acids, bases or salts; some are sugars

Indicators• A substance used to discover the

presence of another material. • An acid/base indicator shows the

presence of one or the other by changing colour.

• Examples include: phenolphthalein, bromothymol blue, pH paper, blue and red litmus paper.

pH scale • A scale that

measures the relative acidity or alkalinity of a substance.

• Based on the concentration of H+

(aq) in a solution