1The Chemistry of Acids and Bases

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Acid and Bases

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Acid and Bases

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Acid and Bases

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Some Properties of Acids

þ Produce H+ (as H3O+) ions in water (the hydronium ion is a

hydrogen ion attached to a water molecule)

þ Taste sour

þ Corrode metals

þ Electrolytes

þ React with bases to form a salt and water

þ pH is less than 7

þ Turns blue litmus paper to red “Blue to Red A-CID”

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Some Properties of Bases

☑ Produce OH- ions (hydroxide) in water

☑ Taste bitter, chalky

☑ Are electrolytes

☑ Feel soapy, slippery

☑ React with acids to form salts and water

☑ pH greater than 7

☑ Turns red litmus paper to blue “Basic Blue”

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Some Common Bases

NaOH - sodium hydroxide lye, drain cleaner

KOH - potassium hydroxide liquid soap

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Acid Strength

The strength of an acid refers to its tendency to lose a proton (H+).

A strong acid is one that completely ionizes (breaks up) in water.

A strong acid is a strong electrolyte

Example:

HCl(aq) → H+(aq) +Cl−(aq)

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Weak Acids

A weak acid only partially ionizes in water.

Ex: carbonic acid (H2CO3)acetic acid (CH3COOH).

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Strength of Bases

Strong bases Ionize completely, OH-Strong bases are strong electrolytes.

Weak bases Only ionize to a limited extent in waterAre weak electrolytes

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ACID-BASE REACTIONSNeutralization Reaction

Similar reactions with weak acids or bases will not result in a neutral solution

An acid with a base produces water and a salt.

HCl + NaOH → NaCl + H2O

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The pH scale is a way of expressing the strength of acids and bases. Instead of using very small numbers, we just use the NEGATIVE power of 10 on the Molarity of the H+

(or OH-) ion.

0 - 7 = acid7 = neutral

7 -14 = base

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pH of Common Substances

14pH indicators• Indicators are dyes that can be

added that will change color in the presence of an acid or base.

• Some indicators only work in a specific range of pH

• Once the drops are added, the sample is ruined

• Some dyes are natural, like radish skin or red cabbage

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Water is AMPHOTERICH2O can function as both an ACID and a BASE.In pure water there can be AUTOIONIZATION

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