Hydrogen sulfate anion

Notice m the following example that a proton adds to the carbon that has the greater number of hydrogens and the hydrogen sulfate anion ( OSO2OH) adds to the carbon that has the fewer hydrogens... 

Sulfuric acid is normally used instead of hydrochloric acid in the diazotization step so as to minimize the competition with water for capture of the cationic intermediate Hydrogen sulfate anion (HS04 ) is less nucleophilic than chloride... 

A constant pH = 3 value, was selected to start the experiments. It was made up with H2SO4 without or with potassium hydrogenophthalate (PHP) and the appropriate concentration of Li2SO4 or LiCl to maintain the total concentration of Li+ constant. First pH measurements illustrated by Fig. 10 give some insight into the acid-base equilibria of the oxidized form of the crown complex. Proton consumption occurs even with the smallest concentration of POM used in that work. The results are easily explained by taking into account the buffer capacity of the various media. A fast increase of the pH is observed in chloride medium as a consequence of the absence of any buffer capacity. In pure sulfate solution, the hydrogen sulfate anion [HSO.y] confers some... 

At the front edge of the band the uranium ions displace hydrogen ions that are bound as hydrogen sulfate anions as in reaction [lEbj ... 

Both perchloric acid and sulfuric acid have an 0-H group, and the acidic proton is part of an 0-H unit for both acids. Any differences in bond strength may be due to differences in the sulfur versus the chlorine. The covalent radii of S is 102 pm and that of Cl is 99 pm, so there is minimal difference. If there is little difference in bond strength in the acids, there may be more subtle factors a simple expedient is to examine the conjugate bases. The hydrogen sulfate anion has an ionic radius of 221 ppm, whereas the perchlorate anion has an atomic radius of 225 ppm. There is little difference in the size of the anions. 

Draw all resonance forms of the hydrogen sulfate anion. 

This question states that HCl is more acidic. If we look at the two reactions, we find that the hydrogen sulfate anion is resonance stabilized and should be more stable than the chloride ion. The HCl bond is more polarized than the OH bond, however, and the chloride ion can be solvated more efficiently by the solvent (water). For these two reasons, HCl in water tends to be the stronger acid. 

This analysis translates into a mechanism where the C=C unit in 2-methyl-2-butene reacts as a base with the acidic proton of sulfuric acid (H2SO4) as the first step, generating the more stable tertiary carbocation 30 rather than the less stable regioisomeric secondary carbocation. Only two nucleophiles are present in the medium water and the hydrogen sulfate anion water is (a) present... 

Draw all resonance forms for the hydrogen sulfate anion, the conjugate base of sulfuric acid. Now replace the OH of the hydrogen sulfate anion with OR, where R is methyl, and draw all resonance forms associated with the sulfonate anion in Figure 11.2. 

On the other hand, the hydrogen sulfate anion is sufficiently basic that it can remove a P-hydrogen from 39, leading to the cyclohexene product. The mqjor product of this reaction is cyclohexene (40), the El product. In most El reactions, an aqueous medium is used to generate the carbocation, so water is available as a nucleophile. The El product can be formed when secondary and tertiary alcohols react with concentrated sulfuric acid or concentrated perchloric acid. When a good nucleophile is present, as in a dilute aqueous solution of sulfuric acid, Sfjl products usually dominate (such as the alcohol product when a carbocation reacts with water). In general, the El reaction is a nuisance in that El products are formed as minor products when a carbocation is generated, even when the S l product is the mqjor one. 

The bisulfate (or hydrogen sulfate) anion, HS04, is a weak acid.The equilibrium constant for the aqueous acid reaction... 

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