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in soln, only H is released.

O . O . H–O–S–O–H . oxyacids : . contain O . H 2 O splits a particle where the polarity is greatest. Consider H 2 SO 4 (an acid) and Ca(OH) 2 (a base). H–O–Ca–O–H . The electronegativity of S is similar to that of O, so the S–O bonds are covalent. This means that….

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in soln, only H is released.

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  1. O O H–O–S–O–H oxyacids: contain O H2O splits a particle where the polarity is greatest. Consider H2SO4 (an acid) and Ca(OH)2 (a base). H–O–Ca–O–H The electronegativity of S is similar to that of O, so the S–O bonds are covalent. This means that… The electronegativity of Ca is low, while for O, it is high. Thus, the Ca–O bonds are ionic. This means that… in soln, only H is released. in soln, the entire OH– group is released.

  2. Anything that draws e– density AWAY from the “donate-able” H makes for a stronger acid.

  3. Other tips: (1) For oxyacids, acid strength generally increases with increasing electronegativity of the central atom. e.g., HClO stronger HBrO (because ENCl > ENBr > ENI) HIO weaker (2) For oxyacids with the same central atom, acid strength increases as the number of oxygens attached to the central atom increases. weaker e.g., HClO HClO2 HClO3 HClO4 stronger

  4. O –C–O–H e.g., CH3COOH vs. CF3COOH carboxyl group Carboxylic acids contain the ____________. –COOH -- these comprise the largest category of organic acids -- acid strength increases with the addition of more electronegative atoms weaker stronger

  5. e– pair acceptors e– pair donors + [ ] H+ + H H :N–H H–N–H H H Gilbert Lewis (1875–1946) Lewis Acids and Lewis Bases L acid L base B–L acid B–L base The “Lewis” definitions greatly broaden the range of acids because many species other than H-containing ones can accept an e– pair.

  6. + F F F–B F–B–N–H H H :N–H F F H H Another example: L acid L base The simple term “acid” suggests that we are referring to an Arrhenius or a Bronsted-Lowry acid, i.e., an H- containing substance in an aqueous solution. If you are referring to a Lewis acid, then use the term “Lewis acid.”

  7. Solutions w/the Fe3+ ion exhibit a characteristic orange color and are generally acidic. H H H O–H : H–O H–O : : : : : e– pair acceptor (L acid) Substances with an incomplete octet (e.g., BF3) or ones having vacant orbitals (e.g., Fe3+) can function as Lewis acids. -- this is why solns of many metal ions exhibit acidic properties -- The (+) charge attracts (i.e., accepts) the lone pairs of e– on the O of a water molecule. This process is hydration: the “glomming” of H2O m’cules onto metal ions. Fe3+

  8. H H H–O H–O : : : : Cation size and cation charge determine the extent to which the pH is affected. K+ Fe3+ -- short distance -- larger distance -- strong interaction -- weaker interaction -- O–H becomes more polarized, and “more polarized” = “stronger acid” -- O–H bond keeps ~ same polarity; acidity is unaffected (i.e., H+s more likely to pop off)

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