acids+and+bases


 * //Acids and Bases// **


 * Video**

Common reactions with metals and acids || media type="custom" key="24057514" Acids, alkalis and salt formation || media type="custom" key="24057584" The difference between strong/weak acids and bases ||
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Reactions of a weak polyprotic acid || media type="custom" key="24059340" Conjugate pairs and amphoteric substances ||
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 * Common Misconceptions:**
 * When a 'proton donor' acid reacts, the nucleus of an atom loses a proton.
 * A neutral solution always has a pH equal to 7.
 * Only pH values of 1-14 exist.
 * Strong acids will have strong conjugate bases.
 * OH- can only act as a base.
 * Water can't be an acid or a base because it is neutral (pH = 7).


 * Interesting facts:**
 * When we speak of acids as proton donors we are talking about the single proton in a hydrogen ion, H+, not a proton from the nucleus of some other atom. Although chemists commonly refer to acids and bases as proton donors and proton acceptors, it is important to realize that H+ is being moved from one chemical species to another, not a proton from one nucleus to another. Furthermore, if nuclear protons //were// transferred, then elements would change their identities in acid-base reactions, since the atomic numbers of the atoms involved would be altered.
 * The percent of water molecules that ionizes depends a great deal on temperature. Only at 25 degrees C does [H+] x [OH-] = 10-14, giving a pH of 7 at neutrality. As temperature increases so does the percent of water molecules that ionize. Thus, at higher temperatures the pH of neutrality decreases. At body temperature, 37 degrees C, the pH of neutral water is 6.81.
 * The definition of pH(-log H+) permits values outside the 1-14 range, although they are seldom encountered. Substituting molarity of commercial concentrated hydrochloric acid (12M) in the definition equation gives a pH = -1.1; for 18 M sulfuric acid, the pH = -1.3. Similarly, the 8 M sodium hydroxide solution used to make soap from animal fat has a pH = 14.9.
 * Sulfuric acid used to be known as 'oil of vitriol' because it was obtained by heating heating 'green vitriol' (iron(II) sulfate).
 * Bases feel slippery to the touch because they react with fats in our skin to form soap.
 * The stronger an acid is, the weaker its conjugate base will be. Strong acids completely dissociate, so their conjugate bases have negligible tendencies to become protonated
 * Weak acids will have weak conjugate bases because they only partially dissociate in an aqueous solution. Their conjugate bases show a slight tendency to abstract protons from water, therefore these conjugate bases are weak. E.g: Acetic acid is a weak acid; acetate ion (conjugate base) is a weak base.
 * OH- can act as a very weak acid by donating its proton to form the very strong base O2-.
 * Water acts as an amphoteric substance.


 * Resources:**
 * Elements of Chemistry: Acids and Bases from Discovery Education.
 * Acid-Base Equilibria from Bergen County.