An industrial chemical reactor treats mineral ores with hot sulfuric acid spray. The temperature inside the treatment chamber can reach up to 310 ∘C310\ ^\circ\text{C}310 ∘C. Additionally, the environment is extremely corrosive due to the concentrated sulfuric acid (H2SO4\text{H}_2\text{SO}_4H2SO4) mist. A chemical engineering company is designing a suspended monitoring sensor to hang inside the chamber. To minimize stress on the overhead support cable, the weight of the sensor must be kept as low as possible. The sensor must also withstand the high temperature and the highly acidic mist.
The table below lists some properties of metals that could be used to construct the outer body of the sensor.
MetalMelting point (∘C)Relative densityReaction with sulfuric acidMagnesium6501.7reacts violentlySilver96210.5no reactionIron15387.9reacts rapidlyBismuth2719.8reacts slowlyZirconium18556.5no reactionZinc4207.1reacts vigorously \begin{array}{|l|c|c|l|} \hline \textbf{Metal} & \textbf{Melting point } (^\circ\text{C}) & \textbf{Relative density} & \textbf{Reaction with sulfuric acid} \\ \hline \text{Magnesium} & 650 & 1.7 & \text{reacts violently} \\ \hline \text{Silver} & 962 & 10.5 & \text{no reaction} \\ \hline \text{Iron} & 1538 & 7.9 & \text{reacts rapidly} \\ \hline \text{Bismuth} & 271 & 9.8 & \text{reacts slowly} \\ \hline \text{Zirconium} & 1855 & 6.5 & \text{no reaction} \\ \hline \text{Zinc} & 420 & 7.1 & \text{reacts vigorously} \\ \hline \end{array} MetalMagnesiumSilverIronBismuthZirconiumZincMelting point (∘C)65096215382711855420Relative density1.710.57.99.86.57.1Reaction with sulfuric acidreacts violentlyno reactionreacts rapidlyreacts slowlyno reactionreacts vigorouslyUse the information in the table to answer the following questions:
(i) Which metal in the table could be used to make a sensor with the lowest density? (ii) Why would this metal be unsuitable for the sensor's outer casing?
Bismuth is commonly used in low-temperature safety fuses. Why would bismuth not be suitable for use in the electrical connections or joints of this sensor?
Choose a metal from the table that would be the most suitable for making the structural casing of the sensor. Give two reasons for your choice.
