Question

Which of the following is most acidic?

• A. $H_{2}O$
• B. $H_{2}S$
• C. $H_{2}Se$
• D. $H_{2}Te$

Answer 1

Answer: (D)

$H_{2}Te$

The acidic nature of hydrides of group-$16$ elements increases from $H_{2}O$ to $H_{2}Te$

The increase in acidic nature of hydrides on moving down the group may be explained in terms of bond length of $H-M$ bond.

Larger the atom, larger is bond length, lesser is bond energy and thus easier is ionization of $H-M$ bond or easier is proton donor nature.

Option D is correct.