Q89E - Chemistry (OpenStax)

Question

Which is the stronger acid, \({{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}\) or  \({{\rm{H}}_2}{\rm{Se}}{{\rm{O}}_4}\)? Why? You may wish to review the chapter on acid-base equilibrium.

 

Step-by-Step Solution

Answer

Therefore, this will result in the easier release of hydrogen in \({{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}\), making it a stronger acid.

 

Step 1: To find the stronger acid.

 

If we compare two acids, such as\({{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}\)and \({{\rm{H}}_2}{\rm{Se}}{{\rm{O}}_4}\) where\({\rm{S}}\) and \(Se\) have the same oxidation number, stronger is the one with a higher electro negativity of a central atom. 

 

Electro negativity of\({\rm{S}}\)is \(2.5\), while the electro negativity of \(Se\) is\(2.4\).

 

Since sulfur is more electronegative than selenium, the shared electron pair between the central atom and\(O\)will be more attracted by sulfur in\({{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}\)than selenium in \({{\rm{H}}_2}{\rm{Se}}{{\rm{O}}_4}\). 

 

This will result in the easier release of hydrogen in \({{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}\), making it a stronger acid.