JEE Main2017Chemistryp Block Elements (Group 15, 16, 17 & 18)Actual
The number of P - OH bonds and the oxidation state of phosphorus atom in pyrophosphoric acid H 4 P 2 O 7 , respectively are:
Options
- AFive and four.
- BFour and five.
- CFive and five.
- DFour and four.
Correct answer
B. Four and five.
Step-by-step solution
As we can clearly see in the structure, the number of P − OH bonds is 4. The oxygen is an electronegative element and will always carry a negative charge. Now, it depends on its surrounding atoms about what charge it carries. In case of a hydroxyl group, the hydrogen carries a +1 charge. So, the opposite charge generated on the oxygen atom along with magnitude will be -1. In the case of only oxygen atoms, we know that the oxidation number of oxygen is equal to -2. So, the charge generated on the adjacent atom