Chemical reactions involve interaction of atoms and molecules. A large number of atoms/molecules (approximately 6.023 $$\times$$ 10$$^{23}$$) are present in a few grams of any chemical compound varying with their atomic/molecular masses. To handle such large numbers conveniently, the mole concept was introduced. This concept has implications in diverse areas such as analytical chemistry, biochemistry, electrochemistry and radiochemistry. The following example illustrates a typical case, involving chemical/electrochemical reaction, which requires a clear understanding of the mole concept. A 4.0 molar aqueous solution of NaCl is prepared and 500 mL of this solution is electrolysed. This leads to the evolution of chlorine gas at one of the electrodes (atomic mass : Na = 23, Hg = 200; 1 Faraday = 96500 coulombs)

If the cathode is a Hg electrode, the maximum weight (g) of amalgam formed from this solution is:

Chemical reactions involve interaction of atoms and molecules. A large number of atoms/molecules (approximately 6.023 $$\times$$ 10$$^{23}$$) are present in a few grams of any chemical compound varying with their atomic/molecular masses. To handle such large numbers conveniently, the mole concept was introduced. This concept has implications in diverse areas such as analytical chemistry, biochemistry, electrochemistry and radiochemistry. The following example illustrates a typical case, involving chemical/electrochemical reaction, which requires a clear understanding of the mole concept. A 4.0 molar aqueous solution of NaCl is prepared and 500 mL of this solution is electrolysed. This leads to the evolution of chlorine gas at one of the electrodes (atomic mass : Na = 23, Hg = 200; 1 Faraday = 96500 coulombs)

The total charge (coulombs) required for complete electrolysis is:

Tollen's reagent is used for the detection of aldehyde when a solution of $\mathrm{AgNO}_3$ is added to glucose with $\mathrm{NH}_4 \mathrm{OH}$ then gluconic acid is formed.

$$ \begin{array}{r} \mathrm{Ag}^{+}+e^{-} \rightarrow \mathrm{Ag} ; \quad \mathrm{E}_{\text {red }}^{\mathrm{o}}=0.8 \mathrm{~V} \\ \mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+\mathrm{H}_2 \mathrm{O} \rightarrow \text { Gluconic acid }\left(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_7\right) +2 \mathrm{H}^{+}+2 e ; \\ \mathrm{E}_{\text {oxd }}^{\mathrm{o}}=-0.05 \mathrm{~V} \\ \mathrm{Ag}\left(\mathrm{NH}_3\right)_2^{+}+e^{-} \rightarrow \mathrm{Ag}(\mathrm{~s})+2 \mathrm{NH}_3 ; \\ \mathrm{E}_{\text {red }}^{\mathrm{o}}=0.337 \mathrm{~V} \end{array} $$

[Use $2.303 \times \frac{\text { RT }}{\text { F }}=0.0592$ and

$$ \left.\frac{\mathrm{F}}{\mathrm{RT}}=38.92 \text { at } 298 \mathrm{~K}\right] $$

$$ \begin{array}{r} 2 \mathrm{Ag}^{+}+\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+\mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{Ag}(\mathrm{~s})+\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_7 +2 \mathrm{H}^{+} \end{array} $$

Find $\ln \mathrm{K}$ of this reaction.

Tollen's reagent is used for the detection of aldehyde when a solution of $\mathrm{AgNO}_3$ is added to glucose with $\mathrm{NH}_4 \mathrm{OH}$ then gluconic acid is formed.

$$ \begin{array}{r} \mathrm{Ag}^{+}+e^{-} \rightarrow \mathrm{Ag} ; \quad \mathrm{E}_{\text {red }}^{\mathrm{o}}=0.8 \mathrm{~V} \\ \mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+\mathrm{H}_2 \mathrm{O} \rightarrow \text { Gluconic acid }\left(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_7\right) +2 \mathrm{H}^{+}+2 e ; \\ \mathrm{E}_{\text {oxd }}^{\mathrm{o}}=-0.05 \mathrm{~V} \\ \mathrm{Ag}\left(\mathrm{NH}_3\right)_2^{+}+e^{-} \rightarrow \mathrm{Ag}(\mathrm{~s})+2 \mathrm{NH}_3 ; \\ \mathrm{E}_{\text {red }}^{\mathrm{o}}=0.337 \mathrm{~V} \end{array} $$

[Use $2.303 \times \frac{\text { RT }}{\text { F }}=0.0592$ and

$$ \left.\frac{\mathrm{F}}{\mathrm{RT}}=38.92 \text { at } 298 \mathrm{~K}\right] $$

When ammonia is added to the solution, pH is raised to 11 . Which half-cell reaction is affected by pH and by how much?