$\ce{Al^3+}$ in water will be hydrated, formed a complex ion $\ce{[Al(H2O)6]^3+(aq)}$ that can neutralize hydroxide ion according to the following reactions:

$$ \begin{align} \ce{[Al(H2O)6]^3+ + OH^- &<=> [Al(H2O)5OH]^2+ + H2O}\tag{1}\\ \ce{[Al(H2O)5OH]^2+ + OH^- &<=> [Al(H2O)4(OH)2]^+ + H2O}\tag{2}\\ \ce{[Al(H2O)4(OH)2]^+ + OH^- &<=> [Al(H2O)3(OH)3]^+ + H2O}\tag{3}\\ \end{align} $$

Which statement is true ?

(A) $\ce{[Al(H2O)6]^3+}$ is a Lewis base
(B) in all reactions $\ce{H2O}$ works as a base
(C) $\ce{[Al(H2O)4(OH)2]^+ }$ is amphiprotic

It is sure that $\ce{Al^3+}$ ion is a Lewis acid and $\ce{H2O}$ is a Lewis base when it is first hydrolize, but I think in the three reaction, $\ce{OH^-}$ work as a Lewis base, so the $\ce{H2O}$ is a conjugate acid right? I confused what is the true answer. Please kindly help me.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.