| A | B |
|---|
| Acid features | Turns blue litmus paper red, pH is lower than 7, conducts well, tastes bitter, turns U from green to red, orange or yellow, is a proton donor (L-B theory) and produces H+ in solution (Arr. theory) |
| Base features | Turns red litmus paper blue, turns U from green to blue, purple, pH higher than 7, conducts poorly, tastes sour, produces OH- in sol ( Arr. theory), Is a proton acceptor (L-B theory) |
| Important Acid base reactions | Acid + Most reactive metals = salt + hydrogen gas, Acid + Metal or Hydrogen carbonate = salt + water + Carbon dioxide, Acid + Metal oxide = salt + water, Acid + Metal hydroxide = salt + water, Acid + metal sulfide = salt + H2S gas, Acid + Metal sufite = Salt + water + SO2 gas, Acid + metal ethanoate = salt +ethanoic acid, Ammonium salt + Base = Water + salt + NH3 (aq), Amphoteric metal + Base + water = Complex ion + H2(g), Amphoteric hydroxide + base = complex ion |
| Amphoteric substances | Can behave as acids or bases, depending on surroundings. They are Al, Cr and Zn. Water can be an amphiprotic substance. |
| Acids - Strong/Weak | Strong acids dissociate completely in aqueos solution, whereas weak acids partially dissociate in solution. |
| Bases - Strong/Weak | Strong bases completely ionise in solution, whereas weak bases partially ionise. |
| Examples of weak bases | Ammonmia, Carbonates, Ethanoate, Flourides and Phosophates |
| Examples of strong bases | Metal hydroxides, metal oxides |
| Conc. annd dilute VS strong and weak | Conc. and dilute describe solution and refer to the amount of solute dissolved in a given volume, wheras strong and weak describe solutes and refer to whether it will dissociate or ionise completely in solution |
| Polyprotic acids | Cpable of donating more than one H+ |
| Electrolyte | Solution that can conduct electricity. Strong ones can ionise/diss. completely. These include ionic solutions and strong A or B. Weak is the reverse (includes H20). Non-E are substances that do not ionise or diss. These are cov molecular. |
| Acidity/Alkalinity of a solution equation | pH = -log [H+], where [H+] can equal 1x10^-14/ [OH-] or n(H+)/V |
| When determining pH | Write an equation, balance it and then look for excess. |
| pH of salt | Salts can be acidic, basic or neutral depending on the acidity of the anion/cation involved in the reaction. Eg. If an ion is basic and the other neutral, than the salt will be basic as the amount of [OH-] > [H+] due to a hydrolysis reaction of that ion |
| Acids, bases and the periodic table | In general the oxides and hydroxides of elements tend to be: More acidic across rge periods, and less acidic down the group |
| Telling the difference between a Salt and Amphoteric salt | Add a littlle acid and then a little base..if reacts with both then it is amphoteric |
