Acids and reactions

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

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) + H2O(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) --> MgCl2(aq) + H2(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) --> CaCl2(aq) + H2O(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) --> CaCl2(aq) + 2 H2O(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. CaCO3(s) + 2 HCl(aq) --> CaCl2(aq) + H2O(l) + CO2(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) --> CaCl2aq) + H2O(l) + CO2(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).