Redox Reactions And Electrochemistry Ques 743
Question: Which of the following are redox reactions-
Options:
A) $ \frac{1}{2}H_2+\frac{1}{2}I_2+HI $
B) $ PCl_5\to PCl_3+Cl_2 $
C) $ 2CuSO_4+4KI\to Cu_2I_2+2K_2SO_4+I_2 $
D) $ CaOCl_2\to C{{a}^{+2}}+OC{{l}^{-}}+C{{l}^{-}} $
Show Answer
Answer:
Correct Answer: A
Solution:
[a] $ \frac{1}{2}{{\overset{0}{\mathop{H}},}_2^{0}}+\frac{1}{2}{{\overset{0}{\mathop{I}},}_2^{0}}\to \overset{+1-1}{\mathop{HI}}, $ ….(i)
$ \overset{+5}{\mathop{P}},\overset{-1}{\mathop{Cl_5}},\to \overset{+3}{\mathop{P}},Cl_3+C\overset{0}{\mathop{I_2}}, $ …..(ii)
$ 2\overset{+2}{\mathop{Cu}},SO_4+4\overset{+1-1}{\mathop{KI}},\to {{\overset{+1}{\mathop{Cu}},}_2}\overset{-1}{\mathop{I_2}},+2K_2SO_4+{{\overset{0}{\mathop{I}},}_2} $ …(iii)
$ \overset{+2}{\mathop{Ca}},O{{\overset{-1}{\mathop{Cl}},}_2}\to C{{a}^{2+}}+OC{{l}^{-}}+C{{l}^{-}} $ …..(iv)
Except (4), there occurs a change in O.S. of the reactants and products. Hence, except (4), all other are redox reactions.
