Question

Rank the following compounds in order of decreasing acid strength using periodic trends.Rank the acids from strongest to weakest. To rank items as equivalent, overlap them.BH3 HBr H2Se H2S

Answer 1

H₂Se is more acidic than H₂S, and HBr is more acidic than BH₃. In a group, from top to bottom, the acidic strength increases. H₂Se is present down in the group than H₂S.  

HBr is more acidic than H₂S, and HBr is more acidic than BH₃. In a period from left to right, there is an increase in the acidic strength. Between HBr and H₂S, HBr is present at the extreme right in the period.  

Hence, the decreasing order of acidic strength is as follows:  

HBr > H₂Se > H₂S > BH₃

Answer 2

HBr>H2S>H2Se>BH3 so basically

1. HBr

2. H2S

3. H2Se

4. BH3