Question

The acidity of the group 16 hydrides increase going down the group (H2O << H2S < H2Se < H2Te). Which is the best explanation for this trend?

(A) The electronegativity of the group 16 elements increases going down the group.

(B) The polarizability of the group 16 elements increases going down the group.

(C) The polarity of the X–H bond increases going down the group.

(D) The H–X–H bond angle increases going down the group.

I don't understand what polarizability means in this particular question. Please explain. From what I understand, acidity increases because atomic radius increases down the group and bonds get bigger I suppose so they are easier to break off.

Thank You!

Answer 1

The answer of the question will be option (C), i.e, acidity of the group 16 hydrides increase going down the group because The polarity of the X–H bond increases going down the group due to increasing size of X and release of proton will be easier. This factor and what is the meaning of polarizability here is explained thoroughly in the attached images.