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Acids & Bases

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Acids

  • HCl
  • H2SO4
  • H3PO4
  • HNO3
  • H2CO3
  • HBr

What do these have in Common?

They all have Hydrogen!

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Acids

  • Acids are compounds that will dissolve in water
  • When dissolved, acids will release H+ ions
  • When a solution has H+ ions it is considered to be acidic.

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Acids

Example When HCl is Dissolved:

HCl → H+ + Cl-

When Hydrochloric acid dissolves

It breaks up into H+ ions and Cl-

Ions.

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Acids

Some weaker acids include:

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  • Vinegar (acetic acid)
  • Ascorbic acid (vitamin C)

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Acids

  • Some other properties of acids:
  • Taste sour (never taste anything in the lab)
  • React with metals to release Hydrogen gas.

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Bases

  • NaOH
  • KOH
  • LiOH

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What do these have in common?

They all have Hydroxide ions!

Hydroxide = OH-

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Bases

  • Bases will dissolve in water and release Hydroxide ions

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  • Example when NaOH is dissolved:

NaOH → Na+ + OH-

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Bases

  • A common base that is more tricky to recognize:

Ammonia (NH3)

NH3 + H2O → NH4+ + OH-

There’s that OH-

Don’t let this scare you . . . you are not expected to know this reaction in Science 10.

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Bases

  • Sodium Bicarbonate

(baking soda)

NaHCO3

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NaHCO3 + H2O → H2CO3 + OH- +Na+

This is why it is a base!

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Bases

Some other properties of bases:

  • Feel slippery (soap)
  • Bitter

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Strength of Acids and Bases

We can predict the strength of acids and bases by using A pH Scale.

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PH Scale

  • A pH of 7 is considered neutral.
  • Under 7 is acidic
  • Over 7 is Basic

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PH Scale

  • Lower number = more acidic
  • Higher number = more basic
  • Example: pH of 1 is more acidic than a pH of 4
  • A pH of 14 is more basic than a pH of 10

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Acid-Base Indicators

  • Indicators are used to determine if a solution is acidic or basic
  • Some indicators include:
    • Red/blue litmus paper
    • Phenophthalein
    • Red cabbage Juice

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Acid-Base Indicators

Blue litmus paper turns red in an acid

Red litmus paper turns

blue in a base

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Acid-Base Indicators

Phenolphthalein turns purple in a basic solution

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Neutralization

  • When mixed, Acids and bases will neutralize each other
  • In general, acid and basic substances react with each other, producing a salt and water and sometimes a gas like carbon dioxide.

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Neutralization

Example:

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HCl + NaOH → HOH + NaCl

This is Just Water (H2O)

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Neutralization

  • What happens when you mix baking soda and vinegar?

NaHCO3 + HC2H3O2 → CO2 + H2O + NaC2H3O2

  • A Neutralization reaction that releases carbon dioxide.
  • The CO2 gas is what makes the mixture foam.

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Applying Concepts

Nelson Science 10

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p. 295

Questions 2-4

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p. 299

Questions 1-4