Weak hase

The titration forms an aqueous solution of a salt derived from a weak hase and a strong acid. The solution should be acidic, which is supported by... 

Subsequently D Alello developed the polystyrene-hased resin in 1944 (4). Two years later, polystyrene anion-exchange resins made hy chloromethylation and amination of the matrix were produced. Four principal classes of ion-exchange resins were commercially availahle by the 1950s. These are the strong-acid, strong-hase, and weak-hase resins derived from styrene-divinylbenzene copolymers, and the weak-acid resins derived from cross-linked acrylics. To this day, the most widely used ion exchangers are synthetic organic polymer resins based on styrene- or acrylic-acid-type monomers as described by D Alelio in U.S. Patent 2,3666,007. 

Example 20-11 shows how we can calculate the concentration of weak hase that is required to initiate precipitation of an insoluhle metal hydroxide. 

Added will not react with Br to any great extent. However, added HNO3 will reduce the soluhihty of AgBr(s) in the ammonia solution. NH3 is a weak hase (fCt = 1-8 X 10 ). Added H will react with NH3 to form NHi. As NH3 is removed, a smaller... 

Multiplying by -1, substituting pKb for -log and rearranging gives another form of the Henderson—Hasselbakh equation for solutions containing a weak hase plus a salt of the weak base. 

Consider the curve shown here for the titration of a weak hase with a strong acid and answer each question. 

When a weak acid is titrated with a strong hase, the curve is quite different. The solution is buffered before the equivalence point. It is basic at the equivalence point because salts of weak acids and strong bases hydrolyze to give basic solutions. So, we can separate the calculations on this kind of titration into four distinct types, which correspond to four regions of the titration curves. 

Classify each of the substances as a weak acid, strong acid, weak base, or strong base in the Arrhenius acid-hase sense. 

Unphosphorylated smooth muscle myosin does not move actin filaments, but does bind actin filaments and keep them associated with the coverslip surface (Umemoto and Sellers, 1990 Warshaw et al., 1990). Occasionally a few filaments can be observed to move over unphosphorylated myosin. As discussed in Chapter 1, this is consistent with the finding that phosphorylated and unphosphorylated smooth muscle HMM have fairly similar binding constants for actin in the presence of ATP (Sellers, 1985). Thus, the weakly bound unphosphorylated myosin heads are able to interact with actin sufficiently well to keep it bound to the surface. If unphosphorylated smooth muscle myosin is mixed in varying ratios with phosphorylated smooth muscle myosin, the rate of in vitro motility is decreased if the fraction of phosphorylated myosin is less than 50% (Warshaw et al., 1990). Unphosphorylated smooth muscle myosin, when mixed with rabbit skeletal muscle myosin, exerts an even more potent inhibitory effect on the rate of movement (Warshaw et al., 1990). Similar findings were also observed if mixtures of myosins are made on beads in the Nitella-hased motility assay (Sellers et al., 1985). 

If the pH is monitored as hase is added to a sample of acetic acid in the course of a titration, an inflection point in the titration curve is reached when the pH equals the pK of acetic acid (Figure 2.13). As we saw in our discussion of the Henderson-Hasselhalch equation, a pH value equal to the pK corresponds to a mixture with equal concentrations of the weak acid and its conjugate base—in this case, acetic acid and acetate ion, respectively. The pH at the inflection point is 4.76, which is the pK of acetic acid. The inflection point occurs when 0.5 mol of hase has been added for each mole of acid present. Near the inflection point, the pH changes very little as more base is added. 

SECTION 16.7 Weak bases include NH3, amines, and the anions of weak acids. The extent to which a weak base reacts with water to generate the corresponding conjugate acid and OH is measured by the base-dissociation constant, Ki,. This is the equilibrium constant for the reaction B(aq) + HjOU) HB (aq) + OH" (aq), where B is the hase. 

Both E2 and El reactions are acid-base reactions. The E2 reaction requires a strong hase, but El reactions occur even with weak bases 2, 3, 4, 6, 7, 9, 21, 25, 26. 

Undo-stand the key events in precipitation and acid-hase reactions and use ionic equations to descrihe them distinguish between strong and weak acids and bases and... 

Appelt S, Hasing FW, Sieling U, Gordji-Nejad A, Gloggler S, Bliimich B (2010) Paths from weak to strong coupling in NMR. Phys Rev A 81 023420... 

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