Electrochemistry · JEE Main previous year questions

2017 2 questions

1. Q632017 · 8 Apr 2017 · Shift 1

   What is the standard reduction potential (${\mathrm{E}}^{\mathrm{o}}$) for $\mathrm{F}{\mathrm{e}}^{3+}\to \mathrm{Fe}$ ? Given that : $\mathrm{F}{\mathrm{e}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{Fe};E_{\mathrm{F}{\mathrm{e}}^{2+}/Fe}^o=-0.47\mathrm{V}$ $\mathrm{F}{\mathrm{e}}^{3+}+{\mathrm{e}}^{-}\to \mathrm{F}{\mathrm{e}}^{2+};E_{\mathrm{F}{\mathrm{e}}^{3+}/F{\mathrm{e}}^{2+}}^o=+0.77\mathrm{V}$

   1. A.$-0.057\mathrm{V}$
   2. B.$+0.057\mathrm{V}$
   3. C.$+0.30\mathrm{V}$
   4. D.$-0.30\mathrm{V}$
   Show answer

   Answer: A

2. Q732017 · 8 Apr 2017 · Shift 1

   Consider the following standard electrode potentials (${\mathrm{E}}^{\mathrm{o}}$ in volts) in aqueous solution : | Element | ${\mathrm{M}}^{3+}/M$ | ${\mathrm{M}}^{+}/M$ | |---|---|---| | Al | -1.66 | + 0.55 | | Tl | +1.26 | - 0.34 | Based on these data, which of the following statements is correct ?

   1. A.$\mathrm{T}{\mathrm{l}}^{+}$ is more stable than $\mathrm{A}{\mathrm{l}}^{3+}$
   2. B.$\mathrm{A}{\mathrm{l}}^{+}$ is more stable than $\mathrm{A}{\mathrm{l}}^{3+}$
   3. C.$\mathrm{T}{\mathrm{l}}^{+}$ is more stable than $\mathrm{A}{\mathrm{l}}^{+}$
   4. D.$\mathrm{T}{\mathrm{l}}^{3+}$ is more stable than $\mathrm{A}{\mathrm{l}}^{3+}$
   Show answer

   Answer: C