Question

Which is the weakest hydrohalic acid?
A) HI
B) HBr
C) HCl
D) HF

Answer 1

Hint: Hydrohalic acid is formed by the addition of hydrogen with halides. Halides are nothing but elements belonging to group 17 i.e. Halogen family. They have only one electron less to attain stable electronic configuration. These elements are usually electronegative in nature and have high electron affinity.

Complete answer:
We will look at all the options to answer this question but firstly we will see the trend for the elements present in halogen family
F
Cl
Br
I
Option A) this is an incorrect option as HI is the least electronegative atom.
Option B) this is an incorrect option as the more polar a bond is, the easier it is to remove the proton or hydrogen from the acid.
Option C) this is an incorrect option as HCl is one of the strongest acids known as hydrochloric acid.
Option D) this is a correct option as HF is the weakest hydrohalic acid. It is a weak acid formed by the reaction between hydrogen and a halogen is hydrofluoric acid (HF). We can say that its a weak acid, but actually is extremely powerful and highly corrosive.

Note:
Hydrofluoric acid or HF is an extremely corrosive acid. However, it is a weak acid and not a strong acid because it does not completely dissociate in water (which is the definition of a strong acid) or at least because the ions it forms upon dissociation are too strongly bound to each other for it to act as a strong acid.