Advertisements
Advertisements
प्रश्न
What sorts of informations can you draw from the following reaction ?
\[\ce{{(CN)}_{2(g)} + 2OH-_{(aq)} -> CN-_{(aq)} + CNO-_{(aq)} + H_2O_{(l)}}\]
Advertisements
उत्तर
The oxidation numbers of carbon in (CN)2, CN– and CNO– are +3, +2 and +4 respectively. These are obtained as shown below:
Let the oxidation number of C be x.
(CN)2
2(x – 3) = 0
∴ x = 3
CN–
x – 3 = –1
∴ x = 2
CNO–
x – 3 – 2 = –1
∴ x = 4
The oxidation number of carbon in the various species is:
\[\ce{{(^{+3}CN)}_{2(g)} + 2OH-_{(aq)} -> ^{+2}CN-_{(aq)} + ^{+4}CNO-_{(aq)} + H_2O_{(l)}}\]
It can be easily observed that the same compound is being reduced and oxidised simultaneously in the given equation. Reactions in which the same compound is reduced and oxidised is known as disproportionation reactions. Thus, it can be said that the alkaline decomposition of cyanogen is an example of disproportionation reaction.
APPEARS IN
संबंधित प्रश्न
Justify that the following reaction is redox reaction:
\[\ce{2K(s) + F2(g) → 2K+F– (s)}\]
Suggest a list of the substances where carbon can exhibit oxidation states from –4 to +4 and nitrogen from –3 to +5.
Identify the substance oxidised, reduced, oxidising agent and reducing agent for the following reaction:
\[\ce{2AgBr (s) + C6H6O2(aq) → 2Ag(s) + 2HBr (aq) + C6H4O2(aq)}\]
Identify the substance oxidised, reduced, oxidising agent and reducing agent for the following reaction:
\[\ce{N2H4(l) + 2H2O2(l) → N2(g) + 4H2O(l)}\]
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
Identify the correct statements with reference to the given reaction.
\[\ce{P4 + 3OH- + 3H2O -> PH3 + 3H2PO^{-}2}\]
(i) Phosphorus is undergoing reduction only.
(ii) Phosphorus is undergoing oxidation only.
(iii) Phosphorus is undergoing oxidation as well as reduction.
(iv) Hydrogen is undergoing neither oxidation nor reduction.
\[\ce{MnO^{2-}4}\] undergoes disproportionation reaction in acidic medium but \[\ce{MnO^{-}4}\] does not. Give reason.
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.
Write redox couples involved in the reactions given.
\[\ce{Cu + Zn^{2+} ->Cu^{2+} + Zn}\]
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?
For the decomposition reaction \[\ce{NH2COONH4 (s) <=> 2NH3 (g) + CO2 (g)}\] the Kp = 2.9 × 10-5 atm3. The total pressure of gases at equilibrium when 1 mol of \[\ce{NH2COONH4 (s)}\] was taken initially could be ______.
