In which one of the following reactions is the underlined species acting as an oxidising agent?
2 Likes
Oxidation/Reduction Recall:
OILRIG
Oxidation is loss of electrons
Reduction is gain of electrons
What is an oxidizing agent?
Causes oxidation in another species (and is reduced itself)
What is a reducing agent?
Causes reduction in another species (it itself is oxidized)
A reduction in oxidation number means that reduction has occur. A rise in oxidation number means that oxidation occurred.
Oxidation Numbers
What are the general rules for assigning an oxidation number?
- For an atom in its elemental form (INCLUDING DIATOMIC ATOMS - HOFBrINCl): Oxidation # = 0
- For a monatomic ion: Oxidation # = charge of ion
- The sum of the oxidation numbers for the atoms in a molecule/compound = 0.
- The sum of the oxidative numbers in a polyatomic ion = charge of ion.
Summary of most common oxidation numbers
Group 1 (+1), Group 2 (+2), H (+/-1), F (-1), O (-2), Group 7 (-1)
A.
Oxidation Numbers:
Cl_2 : 0
2KBr : K (+1), Br (-1)
2KCl : K (+1), Cl(-1)
Br_2: 0
(Cl_2 reduced, therefore is an oxidizing agent)
\fcolorbox{red}{grey!30}{Therefore the answer is A}
B.
Oxidation Numbers:
Zn : 0
CuSO_4 : Cu (+2), S(+6), O(-2)
ZnSO_4 : Zn(+2), S(+6), O(-2)
Cu: 0
(Zn is oxidised and therefore is a reducing agent).
C.
Oxidation Numbers:
CO : C(+2), O(-2)
Fe_2O_3 : Fe (+3), O (-2)
CO_2 : C(+4), O(-2)
Fe: 0
(CO is oxidised and therefore is a reducing agent).
D.
Oxidation Numbers:
H_2SO_4 : H(), S(), O()
NaOH : Na (+1), O (-2), H(+1)
Na_2SO_4: Na(+1), S(+6), O(-2)
H_2O: H(+1), O(-2)
(H_2SO_4 is oxidised and therefore is a reducing agent).
E.
Oxidation Numbers:
Mg : 0
O_2 : 0
MgO : Mg(+2), O(+2)
(Mg is oxidised and therefore is a reducing agent).
1 Like