Question

The dissolution of $Al\left(O H\right)_{3}$ by a solution of $NaOH$ results in the formation of:

• A. $\left[ Al \left( H _{2} O \right)_{4}( OH )_{2}\right]^{+}$
• B. $\left[A l \, \left(H_{2} O\right)_{3} \left(O H\right)_{3}\right]$
• C. $\left[ Al \left( H _{2} O \right)_{2}( OH )_{4}\right]^{-}$
• D. $\left[A l \, \left(H_{2} O\right)_{6} \left(O H\right)_{3}\right]$

Answer 1

Answer: (C)

$Al\left(O H\right)_{3}$ dissolve in $NaOH$ solution to give $Al\left(O H\right)_{4}^{-}$ ion which is supposed to have the octahedral complex species $\left(\left[A l \left(O H\right)_{4} \left(H_{2} O\right)_{2}\right]\right)^{-}$ in aqueous solution
$Al ( OH )_{3}+ NaOH ( aq ) \rightarrow\left[ Al ( OH )_{4}\left( H _{2} O \right)_{2}\right]^{-}( aq )+ Na ^{+}( aq )$