1 common rxn types double displacement precipitation rxns acid-base rxns oxidation-reduction rxns...

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Common Rxn TypesCommon Rxn Types• Double Displacement Precipitation Rxns

• Acid-Base Rxns

• Oxidation-Reduction Rxns (Redox)– Combustion

– Single Displacement

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Double Displacement Rxns The solubility rules are also used to predict whether

or not a double displacement rxn occurs. Double displacement rxns are also called double

replacement or metathesis rxns. In these rxns, the “cations” of the 2 reactants swap

places. The general form is:

Do you see how the cations swapped places?

AX + BY → AY + BX

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Double Displacement Rxns The rxn occurs between 2 ionic compounds in

aqueous solution OR between a strong acid and an ionic compound.

If the rxn is between 2 ionic compounds it is called a double displacement precipitation (ppt) rxn as a ppt is formed. (What a mouthful!)

AX + BY → AY + BXHX + BY → HY + BX

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Double Displacement Rxns For a double displacement ppt rxn to occur between

2 aqueous ionic compounds, a ppt MUST be formed.

What does this mean?

Since the rxn is conducted in water, 1 of the products

MUST be insoluble in water!

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Double Displacement Rxns Here’s an example:

A silver nitrate sln is mixed with a sodium chloride sln. Does this rxn occur, and if so, write the balanced equation.

Here’s another example:

A barium nitrate sln is mixed with a sodium phosphate sln.

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Double Displacement Rxns Your Turn: For the following, write the names of

the possible products, determine whether the rxn occurs, and if it does, write the balanced equation.

1. A sodium chromate sln is mixed with a potassium hydroxide sln.

2. An aluminum nitrate sln is mixed with potassium carbonate.

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Acids & Bases• You’ve learned a very simple definition of acids and

bases.

– Acids produce H+ in water

– Bases produce OH- in water

• You’ve learned the 7 strong acids.

• You’ve learned that the soluble hydroxide salts are

strong bases.

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Acids & Bases• There are also polyprotic acids like sulfuric acid.

• Sulfuric acid can lose both protons, and it does so in

two steps.

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Acid-Base Rxns There are two types of Acid-Base Rxns:

Acid-Base Neutralization Rxns

Acid-Base Gas Evolution Rxns

Both of these rxns are actually a type of Double Displacement Rxns (“cations” swap places)

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Acid-Base Neutralization RxnsAcid-Base Neutralization Rxns

• Acids and bases react with each other in what is called a neutralization rxn.

• They react to form an ionic salt and possibly water or a weak electrolyte.

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Acid-Base Neutralization RxnsAcid-Base Neutralization Rxns

• It was called a neutralization rxn as the classic strong acid/strong hydroxide base rxn resulted in the formation of an ionic salt and water with a pH of 7:

HA(aq) + BOH(aq) → BA(aq) + H2O(l)

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Acid-Base Neutralization RxnsAcid-Base Neutralization Rxns

• Neutralization rxns occur even without strong acids or bases.

• The pH is usually NOT 7 at the end of the rxn.

• Note how the charges change as the acid loses a proton and the base picks it up.

• Group 1 and 2 ionic salts are bases except when bonded to Cl-, Br-, I-, NO3

-, SO42-, ClO4

-, and ClO3-.

HA(aq) + B(aq) → A -(aq) + HB+(aq)

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• This is a type of acid-base rxn where a gas is formed:

Acid-Base Gas Evolution RxnsAcid-Base Gas Evolution Rxns

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Neutralization and TitrationNeutralization and Titration

• Acid-Base Neutralization rxns are often carried out through titrations

• This is a lab technique using burets.• The volume of base required to neutralize a

known volume of acid (or vice versa) is accurately measured in a titration.

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Neutralization and TitrationNeutralization and Titration

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Neutralization and TitrationNeutralization and Titration

• But the math behind a titration is just solution stoichiometry!

• 25.00 mL of an unknown sln of sulfuric acid is completely titrated (in other words, both acidic H’s are stripped from the acid) with 27.64 mL of a 0.502 M sln of sodium hydroxide. What is the molarity of the sulfuric acid sln?

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Neutralization and TitrationNeutralization and Titration

How do you do this?

1) Write balanced equation for the reaction.

2) Do the stoichiometry, using the mol ratios.

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Neutralization and TitrationNeutralization and Titration

• Problem: 10.00 mL of acetic acid is titrated with 12.05 mL of a 0.333M sln of sodium hydroxide. What is the molarity of the acetic acid sln?