Question

Increasing order of acidic strength of halogen acid is

Answer 1

Hint: Acidic strength usually increases with increasing atomic number as the valence electron get away from the nucleus. Weak acid does not donate its hydrogen ions easily. Acidic strength depends upon the size of the atom attached to hydrogen as small atoms get attached to hydrogen the bond will be stronger.

Complete step by step answer:
As fluorine is very electronegative but at the same time its ionic size is small that is why $HF$is considered to be one of the weakest acids.
Now with this criteria either option A or C can be true. $HBr,HCL,HI$ are very strong acids.
The more the bond length between hydrogen and other atoms the more acidic it is in nature. That is why as the size of iodine is the largest the bond length will be more and hence it will have highest acidic strength in all given halogen.
Now $HF$ being the lowest and $HI$ being the highest the order will be $HF < HCL < HBr < HI$

So, the correct answer is Option A.

 Note: The world’s strongest acid is sulphuric acid even though it is one of the least corrosive in nature. Hydrocyanic acid is the weakest acid. Acidic strength increases with increase in electronegativity and oxidation number