Question

Assertion : The strength of haloacids increases in the order : $HI<<HBr<<HCl<<HF$
Reason : Strength of acid $HA$ depends only on the electronegativity difference between $H$ and $A$.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (D)

The correct order of acidic strength is $HF<<HCl<<HBr<<HI$. While comparing elements in the same group of the periodic table, $H—A$ bond strength is a more important factor in determining acidity than its polar nature. As the size of A increases down the group, $H—A$ bond strength decreases and so the acid strength increases.