Question

Arrange in the increasing order of acidity
1 H2O , H2S ,H2Se , H2Te
2 SiH4 , PH3, H2S, HCL

Answer 1

Dear student,

1. H₂O < H₂S < H₂Se < H₂Te
Te is a largest atom among the 16th group elements hence, H₂Te bond is longest and hence it's bond is weakest. Hence it will easily release H+ as compared to other, followed by H₂Se then by H₂S and at last H₂O.
2. SiH₄ < PH₃ < H₂S < HCl
All the elements with H atom are second third period element. The acidic strength increases because of increase in polarity of E- H bond from Si-H to Cl-H which is due to increase in electonegativity of E.
Regards