Short Answer TypeConsider the reactions:
(a) H3PO2(aq) + 4 AgNO3(aq) + 2 H2O(l) → H3PO4(aq) + 4Ag(s) + 4HNO3(aq)
(b) H3PO2(aq) + 2CuSO4(aq) + 2H2O(l) → H3PO4(aq) + 2Cu(s) + H2SO4(aq)
(c) C6H5CHO(l) + 2[Ag (NH3)2]+(aq) + 3OH–(aq) → C6H5COO–(aq)+ 2Ag(s) +4NH3 (aq) + 2H2O(l)
(d) C6H5CHO(l) + 2Cu2+(aq) + 5OH–(aq) → No change observed.
What inference do you draw about the behaviour of Ag+ and Cu2+ from these reactions ?
Long Answer Type| Valencey | Oxidation Number |
| 1. It is the combining capacity of an element in terms of the number of hydrogen atoms with which the element may combine e.g. valency of S in H2S is 2 and that of N in NH3 is 3. | 1. It is the charge which an atom of the element has or appears to have when present in the combined state with their atoms e.g. oxidation number of N in HNO3 is +5. |
| 2. It is purely a number and has no plus or minus sign associated with it. e.g. valency of N in NH3 is 3 and that of H is 1. | 2. It is always assigned plus or minus sign except when it is zero e.g. oxidation number of N in NH3 is -3 and that of H is +1 |
| 3. It is always a whole number. |
3. It may not always be a whole number but may be fractional also. The e.g. oxidation number of Fe in Fe3O4 is +8/3. |
| 4. It is a real concept which can be verified or determined experimentally. | 4. It is a hypothetical concept. Experimental verification or determination is usually not possible. |
Discuss briefly the types of redox reactions. Give examples.
or
Discuss the following redox reactions.
(a) Combination reactions
(b) Decomposition reactions
(c) Displacement reactions
(d) Disproportionation reactions.
Give one example in each case.
Suggest a scheme of classification of the following redox reactions:
(a) N2(g) + O2(g) → 2 NO (g)
(b) 2Pb(NO3)2(s) → 2PbO(s) + 2 NO2 (g) + ½ O2 (g)
(c) NaH(s) + H2O(l) → NaOH(aq) + H2 (g)
(d)2NO2(g) + 2OH–(aq) → NO2-(aq) +NO3–(aq)+H2O(l)
Short Answer TypeRefer to the periodic table given in your book and now answer the following questions:
(a) Select the possible non-metals that can show disproportionation reaction.
(b) Select three metals that can show disproportionation reaction.
Long Answer TypeShort Answer TypeWhat sorts of informations can you draw from the following reaction?
(CN)2(g) + 2OH– (aq) → CN–(aq) + CNO–(aq) + H2O(l)
Suggest a scheme of classification of the given redox reactions,
N2 (g) + O2 (g) 
2NO (g)
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