(i) Account for the following : (a) Acidic character increases from HF to HI.

Question

 Account for the following : 

(a) Acidic character increases from HF to HI. 

(b) There is a large difference between the melting and boiling points of oxygen and sulphur.

(c) Nitrogen does not form pentahalide.

Answer 1

(i) (a) Acidic character increases from HF to HI due to increase in size as a result attraction force decreases and acidity increase.

(b) There is large difference between the melting point and boiling point of oxygen and sulphur due to small size and high electronegativity of oxygen.

(c) Nitrogen does not form pentahalide because of absence of vacant 'd' orbltals.