List of practice Questions

Balance the following redox reactions by ion-electron method: 
(a)MnO4- (aq) + I - (aq) → MnO2(s) + I2(s) (in basic medium)
(b) MnO4- (aq) + SO2(g) → Mn2+(aq) +HSO4- (aq) (in acidic solution)
(c) H2O2(aq)+Fe2+(aq) → Fe3+ (aq) + H2O (l) (in acidic solution)
(d) Cr2O72-+ SO2(g) → Cr3+ (aq) +SO42- (aq) (in acidic solution)
The compound AgF2 is an unstable compound. However, if formed, the compound acts as a very strong oxidizing agent. Why?
Whenever a reaction between an oxidising agent and a reducing agent is carried out, a compound of lower oxidation state is formed if the reducing agent is in excess, and a compound of higher oxidation state is formed if the oxidising agent is in excess. Justify this statement giving three illustrations..
Identify the substance oxidised, reduced, oxidising agent and reducing agent for each of the following reactions:
  1. \(2AgBr (s) + C_6H_6O_2(aq) \rightarrow 2Ag(s) + 2HBr (aq) + C_6H_4O_2(aq)\)
  2. \(HCHO(l) + 2[Ag (NH_3)_2] ^+ (aq) + 3OH^ - (aq) \rightarrow 2Ag(s) + HCOO ^- (aq) + 4NH_3(aq) + 2H_2O(l)\)
  3. \(HCHO (l) + 2Cu^{ 2+}(aq) + 5 OH^ - (aq) \rightarrow Cu_2O(s) + HCOO ^- (aq) + 3H_2O(l)\)
  4. \(N_2H_4(l) + 2H_2O_2(l) \rightarrow N_2(g) + 4H_2O(l)\)
  5. \(Pb(s) + PbO_2(s) + 2H_2SO_4(aq) \rightarrow  2PbSO_4(s) + 2H_2O(l)\)
Assign oxidation numbers to the underlined elements in each of the following species: 
  1. \(NaH_2\underline PO_4\) 
  2. \(NaH\underline SO_4\) 
  3. \(H_4\underline P_2O_7\) 
  4. \(K_2\underline {Mn}O_4\) 
  5. \(Ca\underline O_2\) 
  6. \(Na\underline BH_4\) 
  7. \(H_2\underline S_2O_7\) 
  8. \(KAl(\underline SO_4)_2.12 H_2O\)
What are the oxidation numbers of the underlined elements in each of the following and how do you rationalise your results? 
(a) KI3 (b) H2S4O6 (c) Fe3O4 (d) CH3CH2OH (e) CH3COOH
What sorts of information can you draw from the following reaction?
(CN)2( g)+2OH−(aq)\(\rightarrow\)CN−(2aq)+CNO−(aq)+H2O(l)
Using the standard electrode potentials given below ,predict if the reaction between the following is feasible:
(a) Fe3+(aq) and I- (aq) 
(b) Ag+ (aq) and Cu(s)
(c) Fe3+ (aq) and Cu(s) 
(d) Ag(s) and Fe3+(aq)
(e) Br2(aq) and Fe2+(aq)
Refer to the periodic table given in your book and now answer the following questions:
  1. Select the possible non metals that can show disproportionation reaction. 
  2. Select three metals that can show disproportionation reaction
Consider the elements: \(Cs\), \(Ne\), \(I\) and \(F\)
  1. Identify the element that exhibits only negative oxidation state. 
  2. Identify the element that exhibits only postive oxidation state. 
  3. Identify the element that exhibits both positive and negative oxidation states.
  4. Identify the element which exhibits neither the negative nor does the positive oxidation state.