4. Single Replacement Reacons ‐ A reacve element reacts with an ionic compound
‐ There are two types of Single replacement reacons
o Type 1 – metallic element reacts with an ionic compound
o Type 2 – non‐metallic element reacts with an ionic compound
Type 1 – metallic element reacts with an ionic compound
‐ In this type, the metal element becomes the caon in the compound, and the caon becomes the metal element.
A + BC → B + AC
(metal element) (ionic compound) (new metal element) (new ionic compound)
Word equaon: Magnesium metal is placed in a soluon of aqueous silver nitrate. Magnesium nitrate and solid silver are produced as a result of this chemical reacon.
Skeleton equaon: Mg(s) + AgNO 3(aq) → Mg(NO 3 )2(aq) + Ag (s)
Balanced equaon:
Mg(s) + AgNO 3(aq) → Mg(NO 3 )2(aq) + Ag (s) Type 2 – non‐metallic element reacts with ionic compound
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In this type, the non‐metal element becomes the anion in the new compound, and the anion in the original compound becomes the non‐metal element in the products.
AB + C → AC + B (ionic compound) (non‐metal element) (new ionic compound) (new non‐metal element)
Word equaon: Solid silver bromide reacts with chlorine gas to produce solid silver chloride and liquid bromine
Skeleton equaon:
AgBr (s) + Cl 2(g) → AgCl (s) + Br 2(l)
Balanced equaon: AgBr (s) + Cl 2(g) → AgCl (s) + Br 2(l)
Example 1: aqueous copper (II) nitrate reacts with solid zinc.
Example 2: aqueous lithium bromide reacts with fluorine gas.
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5. Double Replacement Reactions
‐ Occurs most commonly between two ionic compounds. These ionic compounds are usually dissolved in water (aq).
‐ Sometimes, one of the products will form a precipitate as a result of this reaction.
‐ The cations switch places.
AB + CD → AD + CD
(ionic comp.1) (ionic comp. 2) (new ionic comp) (new ionic comp)
Word equation: Aqueous lead(II) nitrate reacts with aqueous potassium iodide to form solid lead (II) iodide and aqueous potassium nitrate
Skeleton equation: Pb(NO3)2(aq) + KI(aq) → PbI2(s) + KNO3(aq)
Balanced equation: Pb(NO3)2(aq) + KI(aq) → PbI2(s) + KNO3(aq)
Practice: Predict the products for the following double replacement reaction. Write the skeleton reaction first. Finally, balance the equations. ***Include the states***
Aqueous copper(I) nitrate and aqueous potassium bromide are mixed. Complete the reaction and balance the equation.
Aqueous sodium chloride and aqueous silver nitrate are mixed together. Complete the reaction and balance the equation.
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