List of top Mineral Processing and Extractive Metallurgy Questions on Reaction Mechanisms & Synthesis

The reaction represented by \( A \rightarrow B \) follows first-order kinetics. At a given temperature, 20% of the reaction is completed in 223 s. The time taken to complete 50% of the reaction at the same temperature is _________ s (rounded off to the nearest integer).
Consider the following reactions and their standard Gibbs free energies (in J): \[ {Fe(s)} + \frac{1}{2} {O}_2(g) \rightleftharpoons {FeO(s)} \quad \Delta G^\circ = -264900 + 65T \] \[ 2 {H}_2(g) + {O}_2(g) \rightleftharpoons 2 {H}_2{O(g)} \quad \Delta G^\circ = -492900 + 109T \] Assuming Fe and FeO to be pure and no solubility of gases in the solids, the value of \( \frac{p_{H_2O}}{p_{H_2}} \) required to reduce solid FeO to solid Fe at 1000 K is _________ (rounded off to two decimal places). Given: Ideal gas constant \( R = 8.314 \, {J mol}^{-1} {K}^{-1} \).
Consider the gas phase reaction: \[ CO + \frac{1}{2} O_2 \rightleftharpoons CO_2 \] At equilibrium for a particular temperature, the partial pressures of \( CO \), \( O_2 \), and \( CO_2 \) are found to be \( 10^{-6} \, {atm} \), \( 10^{-6} \, {atm} \), and \( 16 \, {atm} \), respectively. The equilibrium constant for the reaction is ......... \( \times 10^{10} \) (rounded off to one decimal place).
Molten steel at 1900 K having dissolved hydrogen needs to be vacuum degassed. The equilibrium partial pressure of hydrogen to be maintained to achieve 1 ppm (mass basis) of dissolved hydrogen is ......... Torr (rounded off to two decimal places). Given: For the hydrogen dissolution reaction in molten steel \( \left( \frac{1}{2} {H}_2(g) = [{H}] \right) \), the equilibrium constant (expressed in terms of ppm of dissolved H) is: \[ \log_{10} K_{eq} = \frac{1900}{T} + 2.4 \] 1 atm = 760 Torr.

The reaction represented by \( A \rightarrow B \) follows first-order kinetics. At a given temperature, 20% of the reaction is completed in 223 s. The time taken to complete 50% of the reaction at the same temperature is _________ s (rounded off to the nearest integer).

The reaction represented by A → B follows first order kinetics. At a given temperature, 20\% of the reaction is completed in 223 s. The time taken to complete 50\% of the reaction at the same temperature is ............ s (rounded off to the nearest integer).
Molten steel at 1900 K having dissolved hydrogen needs to be vacuum degassed. The equilibrium partial pressure of hydrogen to be maintained to achieve 1 ppm of dissolved hydrogen is .............. Torr (rounded off to two decimal places).
Match the steel plant related processes in Column I with the associated information in Column II. Column I: P. Corex
Q. Electric Arc Furnace
R. Midrex
S. Continuous Casting
Column II: 1. Melter-gasifier
2. Natural gas reformer
3. Electromagnetic stirrer
4. Hot heel
Which of the following conditions is/are favorable for producing low-silicon hot metal in blast furnace ironmaking?
Match the following elements in Column I with their respective ores in Column II. \begin{center} \begin{tabular}{|l|l|} \hline Column I & Column II
\hline P. Al & 1. Rutile
\hline Q. Fe & 2. Hematite
\hline R. Ti & 3. Chalcopyrite
\hline S. Cu & 4. Bauxite
\hline \end{tabular} \end{center}
Which one of the following slag components is responsible for the oxidizing power of steelmaking slags?
Hot metal from a blast furnace is treated with mill scale prior to oxygen steelmaking for _____.

Consider the gas phase reaction: \[ CO + \frac{1}{2} O_2 \rightleftharpoons CO_2 \] At equilibrium for a particular temperature, the partial pressures of \( CO \), \( O_2 \), and \( CO_2 \) are found to be \( 10^{-6} \, {atm} \), \( 10^{-6} \, {atm} \), and \( 16 \, {atm} \), respectively. The equilibrium constant for the reaction is ......... \( \times 10^{10} \) (rounded off to one decimal place).

In the Fe-C system, the invariant reaction Liquid + $\delta$ $\rightleftharpoons$ $\gamma$ takes place at 1493 °C. This type of reaction is called ______.
Consider the following gas-phase reaction: \[ 2 {SO}_2 + {O}_2 \rightleftharpoons 2 {SO}_3 \] If the enthalpy of reaction is negative, which one of the following conditions promotes a higher equilibrium concentration of SO\(_3\)?

Molten steel at 1900 K having dissolved hydrogen needs to be vacuum degassed. The equilibrium partial pressure of hydrogen to be maintained to achieve 1 ppm (mass basis) of dissolved hydrogen is ......... Torr (rounded off to two decimal places). Given: For the hydrogen dissolution reaction in molten steel \( \left( \frac{1}{2} {H}_2(g) = [{H}] \right) \), the equilibrium constant (expressed in terms of ppm of dissolved H) is: \[ \log_{10} K_{eq} = \frac{1900}{T} + 2.4 \] 1 atm = 760 Torr. 
 

Consider the following reactions and their standard Gibbs free energies (in J): \[ {Fe(s)} + \frac{1}{2} {O}_2(g) \rightleftharpoons {FeO(s)} \quad \Delta G^\circ = -264900 + 65T \] \[ 2 {H}_2(g) + {O}_2(g) \rightleftharpoons 2 {H}_2{O(g)} \quad \Delta G^\circ = -492900 + 109T \] Assuming Fe and FeO to be pure and no solubility of gases in the solids, the value of \( \frac{p_{H_2O}}{p_{H_2}} \) required to reduce solid FeO to solid Fe at 1000 K is _________ (rounded off to two decimal places). Given: Ideal gas constant \( R = 8.314 \, {J mol}^{-1} {K}^{-1} \).