Questions: Construct the expression for Kb for the weak base, N2H4. N2H4(aq) + H2O(l) ⇌ OH^-(aq) + N2H5+(aq) Based on the definition of Kb, drag the tiles into the numerator or denominator to construct the expression for the given base. Kb=

Solution Steps

The given reaction for the weak base hydrazine (\(\mathrm{N}_{2} \mathrm{H}_{4}\)) in water is:

\[ \mathrm{N}_{2} \mathrm{H}_{4}(\mathrm{aq}) + \mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \rightleftharpoons \mathrm{OH}^{-}(\mathrm{aq}) + \mathrm{N}_{2} \mathrm{H}_{5}^{+}(\mathrm{aq}) \]

This reaction shows the base accepting a proton from water, forming hydroxide ions (\(\mathrm{OH}^{-}\)) and the conjugate acid (\(\mathrm{N}_{2} \mathrm{H}_{5}^{+}\)).

The base dissociation constant (\(K_b\)) is defined as the equilibrium constant for the reaction of a base with water. It is given by the expression:

\[ K_b = \frac{[\text{Products}]}{[\text{Reactants}]} \]

For the given reaction, the products are \(\mathrm{OH}^{-}\) and \(\mathrm{N}_{2} \mathrm{H}_{5}^{+}\), and the reactant is \(\mathrm{N}_{2} \mathrm{H}_{4}\).

The expression for \(K_b\) is:

\[ K_b = \frac{[\mathrm{OH}^{-}][\mathrm{N}_{2} \mathrm{H}_{5}^{+}]}{[\mathrm{N}_{2} \mathrm{H}_{4}]} \]

From the given options, the correct tiles to use are:

• \([\mathrm{OH}]\) for \([\mathrm{OH}^{-}]\)
• \([\mathrm{NHH'}]\) for \([\mathrm{N}_{2} \mathrm{H}_{5}^{+}]\)
• \([\mathrm{N:H}]\) for \([\mathrm{N}_{2} \mathrm{H}_{4}]\)

Final Answer