Acid/Base Neutralization • A salt is any compound that can be derived from the neutralization of an acid and a base. • The word “neutralization” is used because the acid and base properties of H+ and OH- are destroyed or neutralized. • In the reaction, H+ and OH- combine to form HOH or H O (water molecules). 2 • A neutralization reaction is a type of double replacement reaction.

Writing neutralization equations When acids and bases are mixed, a salt forms + ─ + ─ NaOH + HCl ® H O + NaCl 2 base + acid ®water + salt The cation (metal) from the base and the anion acid join to form the salt. The OH from the base and the H from the acid join to form water .

Writing neutralization equations Example: Write the chemical reaction when lithium hydroxide is mixed with carbonic acid. Step 1: write out the reactants + ─ + ─ LiOH + H CO ® 2 3 Step 2: determine products…(make sure the salt is written with correct subscripts! Refer to Oxidation Chart.) +1 ─2 Remember the “criss-cross” H O Li CO method-Ch. 20 2 2 3 LiOH + H CO ® Li CO + H O 2 3 2 3 2

Writing neutralization equations Remember balancing equations… Step 3: balance the equation Ch. 21 (use coefficients only) LiOH + H CO ®Li CO + H O 2 2 3 2 3 2 2 lithium hydroxide + carbonic acid ®lithium carbonate + water

Writing neutralization equations Example: Complete the neutralization reaction… Ca(OH) + H SO ® 2 2 4 Step 1: already completed for you + ─ + ─ Ca(OH) + H SO ® 2 2 4 Step 2: determine products…(make sure the salt is written with correct subscripts! Refer to Oxidation Chart.) +2 ─2 Charge of cation equals the H O + Ca SO charge of the anion…no 2 4 need to add subscripts.

Writing neutralization equations Remember balancing equations… Step 3: balance the equation Ch. 21 (use coefficients only) Ca(OH) + H SO ® H O + CaSO 2 2 4 2 2 4 calcium hydroxide + sulfuric acid ®calcium sulfate + water

Writing neutralization equations Example: Complete the neutralization reaction… iron(II) hydroxide + phosphoric acid Step 1: write out the reactants …(make sure the acid and base are written with correct subscripts! Oxidation Chart.) +2 ─1 +1 ─3 Think “criss-cross” Method. Fe OH + H PO ® ( )2 3 4 Fe(OH) + H PO ® 2 3 4

Writing neutralization equations Step 2: determine products…(Is the salt written with correct subscripts? Oxidation Chart.) + ─ + ─ Fe(OH) + H PO ® 2 3 4 +2 ─3 H O + Fe PO 2 4 H O + Fe (PO ) 2 3 4 2 Step 3: balance the equation Remember balancing equations… Ch. 21 (use coefficients only) Fe(OH) + H PO ® H O + Fe (PO ) 3 2 6 2 3 4 2 3 4 2 iron II hydroxide + phosphoric acid ®iron II phosphate + water

Practice Write balanced chemical equations for these neutralization reactions. 1) Ba(OH)2 + HCl 2) calcium hydroxide + nitric acid 3) Al(OH) + H SO 3 2 4 4) KOH + HClO2

a) Ba(OH) + 2HCl ®BaCl + 2H O 2 2 2 barium hydroxide + hydrochloric acid ®barium chloride b) Ca(OH) + 2HNO ®Ca(NO ) + 2H O 2 3 3 2 2 calcium hydroxide + nitric acid ®calcium nitrate c) 2Al(OH) + 3H SO ®Al (SO ) + 6H O 3 2 4 2 4 3 2 aluminum hydroxide + sulfuric acid ®aluminum sulfate d) KOH + HClO ®KClO + H O 2 2 2 potassium hydroxide + chlorous acid ®potassium chlorite

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