Anhydrous is covalent however when it is dissolved in water hydrated ionic species are formed. This transformation is owing to: - Sri Chaitanya Infinity Learn Best Online Courses for NCERT Solutions, CBSE, ICSE, JEE, NEET, Olympiad and Class 6 to 12

A
The trivalent state of Al
B
The large hydration energy of
C
Low hydration energy of
D
The polar nature of water

Solution:

Concept- Chemical compounds are generally of two types: covalent compounds and ionic compounds. Ions with the opposite charge form ionic compounds, usually as a result of the reaction of a metal with a nonmetal. In covalent compounds, the elements form the compound by sharing electrons, resulting in an electrically neutral molecule.
In solution, when

{AlCl}_{3}

dissolves in water, dissociation occurs and

{AlCl}_{3}

dissociates into

{Al}^{+ 3}

and

{Cl}^{-}

. Now, Hydration of

{Al}^{+ 3}

and

{Cl}^{-}

ions occur due to the large hydration energy of

{Al}^{+ 3}

ions as it dissolves in water.
Anhydrous

{AlCl}_{3}

is covalent, but when dissolved in water, hydrated ionic species are formed. This transformation is due to the large hydration energy of

{Al}^{+ 3}

.
Thus, in liquid or gas phase

{AlCl}_{3}

exists as a covalent compound, or as in the form of dimers.
But, when we dissolve

{AlCl}_{3}

in water, it liberates the ions of aluminium (

{Al}^{+ 3}

)and chloride ion (

{Cl}^{-}

).
Hence, the correct answer is 2.

Solution:

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