Question

Give reason an aqueous solution of ammonia act as a weak base

Answer 1

Ammonia molecule contains a lone pair of electrons on N-atom, which accepts a proton from water, and forms ammonium ion and hydroxide ion, this makes ammonia solution alkaline and thus, it acts as a base.

 NH3 + H2O → NH4 + + OH-

However, as the concentration of the hydroxyl ions that are furnished is less, therefore aqueous solution of ammonia acts as a weak base. 

Answer 2

Explanation:

because it undergoes partial dissociation in aqueous solution to give hydronium ions in low concentration

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