InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
Among H_(3)PO_(2), H_(3)PO_(3) and H_(3)PO_(4) which has the maximum acidic strength ? Explain |
|
Answer» Solution :Generally, the acidic strength of oxyacids of an element with DIFFERENT oxidation states increases with the increase in oxidation state of central ATOM. So, the expected order of acidic strength should be `H_(3)PO_(4) gt H_(3)PO_(3) gt H_(3)PO_(2)`. But actual order is `H_(3)PO_(2) gt H_(3)PO_(3) gt H_(3)PO_(4)`. This can be explained BASED on the number of `OH^(-)` groups attached to central P-atom. With increasing number of OH groups on central P-atom the acidic strength decreases. Hence, `H_(3)PO_(4)` is having minimum acidic strength and `H_(3)PO_(2)` is having maximum acidic strength. `underset(H_(3)PO)(H - underset(underset(H)(|))OVERSET(overset(O)(||))(P) - OH) "" underset(H_(3)PO)(H - underset(underset(OH)(|))overset(overset(O)(||))(P) - OH) "" underset(H_(3)PO)(HO - underset(underset(OH)(|))overset(overset(O)(||))(P) - OH)` With the increases in number of `-OH` groups, the strength of conjugate base FORMED increases due to greater proton accepting tendency. Therefore, the strengths of corresponding acids decrease accordingly |
|