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Question
Justify that the following reaction is redox reaction:
\[\ce{CuO(s) + H2(g) → Cu(s) + H2O(g)}\]
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Solution
\[\ce{CuO(s) + H2(g) → Cu(s) + H2O(g)}\]
Let us write the oxidation number of each element involved in the given reaction as:
\[\ce{^{+2}Cu^{-2}O(s) + ^0H2(g) → ^0Cu(s) + ^{+1}H2^{-2}O(g)}\]
Here, the oxidation number of Cu decreases from +2 in CuO to 0 in Cu i.e., CuO is reduced to Cu. Also, the oxidation number of H increases from 0 in H2 to +1 in H2O i.e., H2 is oxidized to H2O. Hence, this reaction is a redox reaction.
RELATED QUESTIONS
Justify that the following reaction is redox reaction:
\[\ce{4BCl3(g) + 3LiAlH4(s) → 2B2H6(g) + 3LiCl(s) + 3 AlCl3(s)}\]
While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why?
Identify the substance oxidised, reduced, oxidising agent and reducing agent for the following reaction:
\[\ce{2AgBr (s) + C6H6O2(aq) → 2Ag(s) + 2HBr (aq) + C6H4O2(aq)}\]
Consider the reactions:
- \[\ce{H3PO2(aq) + 4 AgNO3(aq) + 2 H2O(l) → H3PO4(aq) + 4Ag(s) + 4HNO3(aq)}\]
- \[\ce{H3PO2(aq) + 2CuSO4(aq) + 2 H2O(l) → H3PO4(aq) + 2Cu(s) + H2SO4(aq)}\]
- \[\ce{C6H5CHO(l) + 2[Ag (NH3)2]+(aq) + 3OH–(aq) → C6H5COO–(aq) + 2Ag(s) + 4NH3 (aq) + 2 H2O(l)}\]
- \[\ce{C6H5CHO(l) + 2Cu^{2+}(aq) + 5OH–(aq) → No change observed}\]
What inference do you draw about the behaviour of Ag+ and Cu2+ from these reactions?
Refer to the periodic table given in your book and now answer the following questions:
Select the possible non-metals that can show disproportionation reaction.
Arrange the following metals in the order in which they displace each other from the solution of their salts.
Al, Cu, Fe, Mg and Zn.
Identify disproportionation reaction
Which of the following elements does not show disproportionation tendency?
Which of the following statement(s) is/are not true about the following decomposition reaction.
\[\ce{2KClO3 -> 2KCl + 3O2}\]
(i) Potassium is undergoing oxidation.
(ii) Chlorine is undergoing oxidation.
(iii) Oxygen is reduced.
(iv) None of the species are undergoing oxidation or reduction.
Assertion (A): Redox couple is the combination of oxidised and reduced form of a substance involved in an oxidation or reduction half cell.
Reason (R): In the representation \[\ce{E^Θ_{Fe^{3+}/Fe^{2+}}}\] and \[\ce{E^Θ_{Cu^{2+}/Cu}, Fe^{3+}/Fe^{2+}}\] and \[\ce{Cu^{2+}/Cu}\] are redox couples.
Why does fluorine not show disporportionation reaction?
Write redox couples involved in the reactions given.
\[\ce{Mg + Fe^{2+} -> Mg^{2+} + Fe}\]
Find out the oxidation number of chlorine in the following compounds and arrange them in increasing order of oxidation number of chlorine.
\[\ce{NaClO4, NaClO3, NaClO, KClO2, Cl2O7, ClO3, Cl2O, NaCl, Cl2 , ClO2}\].
Which oxidation state is not present in any of the above compounds?
Which of the following statement is CORRECT for the decomposition reaction of KClO3?
\[\ce{2KClO3 → 2KCl +3O2}\]
Which of the following examples does not represent disproportionation?
An acidified manganate solution undergoes disproportionation reaction. The spin-only magnetic moment value of the product having manganese in a higher oxidation state is ______ B.M. (Nearest integer)
The reaction of sulphur in alkaline medium is given below:
\[\ce{S8(s) + {a} OH^-(aq) -> {b} S^{2-}(aq) + {c} S2O^{2-}3(aq) + {d} H2O(l)}\]
The values of 'a' are ______. (Integer answer)
