Problem 1 // Correct reaction b/w PbS and O3 is represented by
(a) PbS + 2O3 = PbSO4 + O2
(b) PbS + 4O3 = PbSO4 + 4O2
(c) PbS + 6O3 = PbSO4 + 7O2
(d) 3PbS + 4O3 = 3PbSO4
Problem 2 // Equivalent mass of ozone is
Problem 3 // How many mole KI(aq.) reacts with One mole O3 ?
- During reaction, One Ozone molecule gives one O2 molecule and one nascent Oxygen atom, [O]. This nascent oxygen atom gains “two” electrons and becomes “oxide ion” and gets attached to the other substance. Hence
n-factor of ozone is 2 and its equivalent mass = 48/2 = 24
- To balance the reaction b/w PbS and Ozone, there can be answer like, PbS + 2O3 = PbSO4 + O2 and nothing seems wrong at first sight.
- One Ozone molecule really only gives one oxygen atom to the substance it oxidises.
- Here, we must need 4 O3 molecules to provide “four oxygen atom” to convert one PbS molecule into one molecule of PbSO4
- In other words, n-factor of O3 is 2 and “n-factor of PbS is 8” (change in oxidation number of sulfur from -2 to +6). Hence “mole ratio of PbS/O3 must be 2/8 = ¼ .”
- Hence, correct answer is PbS + 4O3 = PbSO4 + 4O2
- Similarly, n-factor of KI is 1 when it converts into I2, hence mole ratio KI/O3 = (2/1).
- 2KI + H2O + O3 = 2KOH + I2 + O2
- Hence answer of each of the above questions is option (B)