1
Oxidation numbers of P in PO43-, of S in SO42- and that of Cr in Cr2O72- are respectively
- +3, +6 and +5
- +5, +3 and +6
- –3, +6 and +6
- +5, +6 and +6
Answer
(4) +5, +6 and +6
Solution
Take O = –2 and equate the sum to the charge of the ion.
PO43-: x + 4(-2) = -3 x = +5
SO42-: x + 4(-2) = -2 x = +6
Cr2O72-: 2x + 7(-2) = -2 x = +6
Answer: (4)
AIPMT 2009