Oxidation state
Answers are for parents and teachers.
1
Calculate the oxidation state of chlorine in HClO₄.
(+1) + x + 4·(–2) = 0, x = +7.
2
Oxidation state of phosphorus in Ca₃(PO₄)₂?
3·(+2) + 2x + 8·(–2) = 0, x = +5.
3
Write nitrogen’s oxidation states in N₂, NH₃, NO, NO₂, HNO₃ in order.
0, –3, +2, +4, +5
4
Oxidation state of chromium in the ion Cr₂O₇²⁻?
2x + 7·(–2) = –2, x = +6.
5
Why can an oxidation state be fractional? Explain with Fe₃O₄.
3x + 4·(–2) = 0, x = +8/3; in fact Fe²⁺ and Fe³⁺ mixed, the average value is a fraction.