The calomel electrode is commonly used as a reference electrode in electrochemical measurements. It consists of mercury (\( \text{Hg} \)) in contact with mercurous chloride (calomel, \( \text{Hg}_2\text{Cl}_2 \)) in a saturated potassium chloride (\( \text{KCl} \)) solution.
The calomel electrode falls under the category of "Metal – Insoluble Salt – Anion electrodes" because it involves a metal (\( \text{Hg} \)), an insoluble salt (\( \text{Hg}_2\text{Cl}_2 \)), and the chloride ions (\( \text{Cl}^- \)) in solution.
The correct answer is Option (1): Metal – Insoluble Salt – Anion electrodes.
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)