IIT-JEE 2007 · Paper 2, Chemistry question 38

Paragraph for Question Nos. 36 to 38

Redox reactions play a pivotal role in chemistry and biology. The values of standard redox potential ($E^\circ$) of two half-cell reactions decide which way the reaction is expected to proceed. A simple example is a Daniell cell in which zinc goes into solution and copper gets deposited. Given below are a set of half-cell reactions (acidic medium) along with their $E^\circ$ (V with respect to normal hydrogen electrode) values. Using this data obtain the correct explanations to Questions 36-38.

Half-cell reaction	$E^\circ$ (V)
$\ce{I2 + 2e- -> 2I-}$	0.54
$\ce{Cl2 + 2e- -> 2Cl-}$	1.36
$\ce{Mn^{3+} + e- -> Mn^{2+}}$	1.50
$\ce{Fe^{3+} + e- -> Fe^{2+}}$	0.77
$\ce{O2 + 4H+ + 4e- -> 2H2O}$	1.23

(The paragraph is not printed in the official archive copy (which reproduces only the questions with their answers); its text is restored from the JEE 2007 question paper.)