Search results
Results From The WOW.Com Content Network
Neutral methylamine molecules are hydrogen-bonded to water molecules mainly through one acceptor, N–HOH, interaction and only occasionally just one more donor bond, NH–OH 2. Hence, methylamines are stabilized to about the same extent by hydration, regardless of the number of methyl groups.
Brønsted and Pederson first discovered the relationship between basicity, with respect to protons, and nucleophilicity in 1924: [3] where = + where k b is the rate constant for nitramide decomposition by a base (B) and β N is a parameter of the equation.
With a pK a of 12.34 [4] for its conjugate acid in aqueous solution, 1,8-bis(dimethylamino)naphthalene is one of the strongest organic bases. However, it only absorbs protons slowly—hence the trade name. The high basicity is attributed to the relief of strain upon protonation and/or the strong interaction between the nitrogen lone pairs. [3]
The "number of basic sites per unit surface area of the solid" is used to express how much basic strength is found on a solid base catalyst. [15] Scientists have developed two methods to measure the amount of basic sites: one, titration with benzoic acid using indicators and gaseous acid adsorption. [15]
The bicarbonate ion carries a negative one formal charge and is an amphiprotic species which has both acidic and basic properties. It is both the conjugate base of carbonic acid H 2 CO 3; and the conjugate acid of CO 2− 3, the carbonate ion, as shown by these equilibrium reactions: CO 2− 3 + 2 H 2 O ⇌ HCO −
It is a highly stable +1 cation in aqueous solution due to the efficient resonance stabilization of the charge and efficient solvation by water molecules. As a result, its p K aH is 13.6 [ 2 ] (p K b of 0.4) meaning that guanidine is a very strong base in water; in neutral water, it exists almost exclusively as guanidinium.
In chemistry a donor number (DN) is a quantitative measure of Lewis basicity.A donor number is defined as the negative enthalpy value for the 1:1 adduct formation between a Lewis base and the standard Lewis acid SbCl 5 (antimony pentachloride), in dilute solution in the noncoordinating solvent 1,2-dichloroethane with a zero DN.
Its conjugate base is the acetate ion with K b = 10 −14 /K a = 5.7 x 10 −10 (from the relationship K a × K b = 10 −14), which certainly does not correspond to a strong base. The conjugate of a weak acid is often a weak base and vice versa .