Acids+and+Bases

Acids and reactions

Do these Questions for this chapter Questions 1,2,3,4,5,6,7,8,9,10
 * CHAPTER 13: INTRODUCING ACIDS.**

Acids are usually sour tasting, can change the colour of Indicators (dyes) and neutralize bases. Examples include Hydrochloric Acid, HCl - for cleaning bricks, Sulfuric Acid, H2SO4 - battery acid, Nitric Acid, HNO3 - dissolves Gold & Silver, Phosphoric Acid, H3PO4 - cleans jewellery and Acetic Acid, CH3COOH - vinegar. Bases or Alkalis also change the colour of indicators and neutralize acids. Examples include Ammonia, NH3 - cleaners, Calcium Hydroxide, Ca(OH)2 - used in plaster and cement, Sodium Hydroxide, NaOH – drain/oven cleaners and Magnesium Hydroxide, Mg(OH)2 - used in aiding indigestion. eg. Litmus and Universal Indicator (a mixture of indicators) turn in acid and purple in a base. Universal Indicator can produce different colours depending upon the concentration of the acid or base.

Reactions of Acids and Bases: a). Neutralisation Of Acids Or Bases: - An Acid will react with a Base to produce a neutral solution of an Ionic Salt and . eg. HCl(aq) + NaOH(aq) --> NaCl(aq) + H 2 O(l). Acid Base Salt Water b). Reaction With Metals:- Acids react with certain Metals to produce a neutral solution of an Ionic Salt as well as releasing H2 gas. eg. Mg(s) + 2 HCl(aq) --> MgCl 2 (aq) + H 2 (g). Only reactive metals (Group I, II & III) will react with acids. Metal Acid Salt Hydrogen c). Reaction With Metal Oxides:- Acids react with certain Metal Oxides to produce a neutral solution of an Ionic Salt and . eg. CaO(s) + 2 HCl(aq) --> CaCl 2 (aq) + H 2 O(l). This is how oxide coatings are removed from structures. Metal Oxide Acid Salt Water d). Reaction With Metal Hydroxides:- Acids react with certain Metal Hydroxides to produce a neutral solution of an Ionic Salt and H2O. eg. Ca(OH) 2 (aq) + 2 HCl(aq) --> CaCl 2 (aq) + 2 H 2 O(l). This can neutralise acidic soils and relieve Metal Hydroxide Acid Salt Water stomach aches (antacids). e). Reaction With Metal Carbonates:- Acids react with Metal Carbonates to produce a neutral solution of an Ionic Salt, H2O and release CO2 gas. eg. CaCO 3 (s) + 2 HCl(aq) --> CaCl 2 (aq) + H 2 O(l) + CO 2 (g). Calcium Carbonate is also called marble Metal Carbonate Acid Salt Water Carbon Dioxide or _ & is used in statues. f). Reaction With Metal Bicarbonates (Hydrogen Carbonates):- Acids react with Metal Bicarbonates to produce a neutral solution of an Ionic Salt & H2O and release CO2 gas. eg. Ca(HCO3) 2 (s) + HCl(aq) --> CaCl 2 aq) + H 2 O(l) + CO 2 (g). In baking powders, this make dough rise Metal Bicarbonate Acid Salt Water Carbon Dioxide & how antacids relieve stomach aches. g). Reaction With Metal Sulfides:- Acids react with some Metal Sulfides to produce a solution of an _ & release H2S gas. eg. FeS(s) + 2 HCl(aq) --> FeCl2(aq) + H2S(g). H2S gas smells like rotten eggs and is toxic. Metal Sulfide Acid Salt Hydrogen Sulfide h). Reaction With Metal Sulfites:- Acids react with some Metal Sulfites to produce a neutral solution of an Ionic Salt & H2O and release SO2 gas. eg. Na2SO3(s) + 2 HCl(aq) --> 2 NaCl(aq) + H2O(l) + SO2(g). Sulfur Dioxide gas is toxic. Metal Sulfite Acid Salt Water Sulfur Dioxide When writing Ionic Equations, include the species that change state, don’t split solids and ignore Spectator Ions: Part a/d): H+(aq) + OH-(aq) --> H2O(l). Part b): 2 H+(aq) + Mg(s) --> Mgx+(aq) + _. Part c): 2 H+(aq) + CaO(s) --> Ca2+(aq) + H2O(l). Part e/f): 2 H+(aq) + CaCO3(s) and 2 H+(aq) + Ca(HCO3)2(s) --> H2O(l) + CO2(g) + Ca2+(aq). Part g): FeS(s) + 2H+(aq) --> H2S(g) + Fe2+(aq). Part h): Na2SO3(s) + 2H+(aq) --> 2Na+(aq) + H2O(l) + SO2(g).