Given below are two statements: In the light of the above statements, choose the correct answer from the options given below
- Statement I is false but Statement II is true
- Statement I is true but Statement II is false
- Both Statement I and Statement II are true
- Both Statement I and Statement II are false
Answer
(3) Both Statement I and Statement II are true
Solution
Statement I: In the titration of oxalic acid with KMnO4 (dil. H2SO4) the oxalic acid solution is warmed to about 60 before titration, because the reaction is very slow at room temperature. In the Mohr's salt (FAS) titration no heating is needed. True.
Statement II: 2MnO4- + 5C2O42- + 16H+ 2Mn2+ + 10CO2 + 8H2O
The first Mn2+ ions (MnSO4) form only at the higher temperature; once formed, Mn2+ catalyses the further reaction (autocatalysis).
In the FAS titration, heating would allow atmospheric oxygen to oxidise Fe2+ to Fe3+, so less KMnO4 would be used and an error would be introduced. True.
Answer: (3)