Neutralization Reactions Ex: HCl + NaOH NaCl + HOH These are double replacement reactions Ions switch partners. Water is formed. http://www.youtube.com/watch?v=8IRI5gPR5EY&safe=active Neutralization Forms Water H+ from acid + OH-  from base H 2O neutral This “net” reaction for neutralization is found on Table I. It is an exothermic reaction. Forming a Salt (+) cation from the base (-) anion from the acid combine to form a salt. If equal concentrations of hydrogen ion H+ and hydroxide ions OH- are mixed, it results in a neutral solution. Ex: .1M LiOH + .1M HCl = Neutral Solution pH = 7 Completing and Balancing Neutralization Equations Write charges for ions in acid and base.  Switch ion partners. (+ ions stay in front!!)  Do not bring over subscripts except if part of a polyatomic ion!  Criss-Cross charges to balance formulas.  Balance entire equation.   Name the acid, base and salt. You Try It Complete equation and balance formulas  Balance equation.  Name acid base and salt  Ex: KOH + H2SO4 KOH + H2SO4 HOH + K2SO4 Ex: Mg(OH)2 + HNO3 Mg(OH)2 + HNO3 HOH + Mg(NO3)2 Hydrolysis  Opposite reaction to neutralization Salt + Water Acid + Base Parent Acid/Base  If you know the salt involved you should be able to determine which acid and base it would form if water is added. Salt + Water Acid + Base Ex: NaCl with water (HOH) would form HCl and NaOH You Try It  Name the “parent” acid and base that would be produced from these salts.  Ex: Potassium chloride Magnesium carbonate Let’s Practice  Which substance is always a product when an Arrhenius acid in an aqueous solution reacts with an Arrhenius base in an aqueous solution? (1) HBr (2) KBr (3) H2O (4) KOH  Which word equation represents a neutralization reaction? (1) base + acid → salt + water (2) base +salt → water + acid (3) salt + acid → base + water (4) salt + water → acid + base  What are the products of a reaction between KOH(aq) and HCl(aq)? (1) H2 and KClO (2) KH and HClO (3) H2O and KCl (4) KOH and HCl  Sulfuric acid, H2SO4(aq), can be used to neutralize barium hydroxide, Ba(OH)2(aq). What is the formula for the salt produced by this neutralization? (1) BaS (3) BaSO3 (2) BaSO2 (4) BaSO4  Which compound could serve as a reactant in a neutralization reaction? (1) NaCl (2) CH3OH (3) KOH (4) CH3CHO Answer: 3 Titrations Purpose: To determine the concentration of an acid or base through a neutralization reaction. Acid/Base Titration Buret is filled with a “standard solution” of known concentration (M). Erlenmeyer Flask contains solution of unknown conc.. Indicator (phenolphthalein) added to the flask. Acid/Base Titrations Slowly “titrate” or drip liquid into flask from buret until indicator changes color. This is the “endpoint” or “equivalence point”. (Moles H+ = Moles OH-) Record total volume (V) used from buret. Titration Formula MA x VA = MB x VB Molarity Acid x Volume Acid = Molarity Base x Volume Base Titration Applet http://group.chem.iastate.edu/Greenbowe/se ctions/projectfolder/flashfiles/stoichiometry /acid_base.html You Try It! A 50 ml sample of .2M HCl is neutralized by 75ml of NaOH. What is the conc. of the base? HCl NaOH .2M x 50ml = MB x 75ml MB = .13M Important Note  Multiply acid/base side of equation by number of H+ or OH- ions it produces when dissociating!!!  Ex: H2SO4 produces 2 H+ so you would multiply the acid side by “2” You Try It! How much of a .1M H2SO4 solution is needed to neutralize 50 ml of a .05 KOH solution? H2SO4 KOH 2 x .1M x VA = .05M x 50ml VA = 12.5 ml Titration Demonstration http://www.youtube.com/watch?v=5BZ0MPI geEE&safe=active Let’s Practice  During which process can 10.0 milliliters of a 0.05 M HCl(aq) solution be used to determine the unknown concentration of a given volume of NaOH(aq) solution? (1) evaporation (2) filtration (3) distillation (4) titration  The data collected from a laboratory titration are used to calculate the (1) rate of a chemical reaction (2) heat of a chemical reaction (3) concentration of a solution (4) boiling point of a solution A student completes a titration by adding 12.0 ml of NaOH(aq) of unknown concentration to 16.0 ml of 0.15 M HCl(aq). What is the molar concentration of the NaOH(aq)? (1) 0.11 M (2) 1.1 M (3) 0.20 M (4) 5.0 M