when potassium permanganate solution is titrated with solution containing Fe2+ ions the indicator used in water litration is-
(a) phenolphthale
(b) methyl orange
(c)methyl red
(d)self indicator
Answers
Kmno4 is used as a indicator , is known as self indicator
self indicator ( Kmno4) :-
some colour solutions itself act as an indicator and during the chemical reaction it changes their colour ,
titration of Fe+2 ion with Kmno4 solution,
is known as redox titration . KMnO4 is changing from violet to colourless .
KMnO4 = potassium permanganate
following reaction as follows,
Fe+2 + 7Mno4- + 14 H+ ---> Fe+3 +7 MN+2 + H2O
=> phenolphthalein , methyl orange , litmus and diphenhydramine are acid base titration indicator
Types of indicators :--
1) Internal indicator
These indicators are added to the solutions which are taking part in the reaction for example methyl orange , phenolphthalein .
2) External indicator:--
These indicators are not added to the solutions . one drop of such indicator is mixed with titrating mixture for example potassium ferricyanide .
3) self - indicator :--
some colour solutions itself act as an indicator and during the chemical reaction it changes their colour There solutions are known as self - indicator for example potassium permanganate .
your answer is (D) self indicator Kmno4 .
hope it helps :)