iran-konkur 2021 Q231

iran-konkur · Other · konkur-riazi_1400_specialized Not Maths
231 – How many of the following statements are correct?
$$E^\circ\!\left[\mathrm{Mn^{2+}(aq)/Mn(s)}\right] = -1.18\,\text{V} \;,\quad E^\circ\!\left[\mathrm{Pt^{2+}(aq)/Pt(s)}\right] = +1.20\,\text{V}$$
  • Hydrogen oxidation in fuel cells has an efficiency close to 60\%.
  • In galvanic cells, the products are more stable than the reactants.
  • In a galvanic cell ``manganese – platinum'', oxidation occurs at the manganese electrode.
  • In every oxidation–reduction reaction, the atoms of oxidized metals and metal ions decrease.

(1) 1 (2) 2 (3) 3 (4) 4

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\textbf{231 –} How many of the following statements are correct?

$$E^\circ\!\left[\mathrm{Mn^{2+}(aq)/Mn(s)}\right] = -1.18\,\text{V} \;,\quad E^\circ\!\left[\mathrm{Pt^{2+}(aq)/Pt(s)}\right] = +1.20\,\text{V}$$

\begin{itemize}
    \item Hydrogen oxidation in fuel cells has an efficiency close to 60\%.
    \item In galvanic cells, the products are more stable than the reactants.
    \item In a galvanic cell ``manganese – platinum'', oxidation occurs at the manganese electrode.
    \item In every oxidation–reduction reaction, the atoms of oxidized metals and metal ions decrease.
\end{itemize}

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(1) 1 \hspace{1.5cm} (2) 2 \hspace{1.5cm} (3) 3 \hspace{1.5cm} (4) 4
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