The metal 'M' with electronic configuration [ Ar]\,3d^104s^2 belongs to group IIB in the periodic table and is commonly called 'Jasta'. a) Identify metal 'M' and write its main ore. [1] b) Why is…

{
  "type": "vertical-retort",
  "label": "Vertical retort for zinc extraction",
  "parts": [
    {"type": "container", "label": "Vertical retort", "position": "center"},
    {"type": "inlet", "label": "Zinc oxide + Coke (C)", "position": "top"},
    {"type": "arrow", "label": "Heated to 1200°C", "from": "top", "to": "middle"},
    {"type": "reaction", "label": "ZnO + C → Zn + CO↑", "position": "middle"},
    {"type": "outlet", "label": "Zinc vapor (Zn)", "position": "top-right"},
    {"type": "outlet", "label": "Carbon monoxide (CO)", "position": "bottom-right"}
  ],
  "caption": "Vertical retort used for the reduction of zinc oxide to extract zinc metal."
}

Answer:

a) Identification and main ore

The metal M with the electronic configuration $[\mathrm{Ar}]3d^{10}4s^2$ belongs to Group 12 (IIB) of the periodic table and is commonly called Jasta (zinc in Nepali). The metal M is zinc (Zn). Its main ore is sphalerite (ZnS).

b) Why zinc is not considered a transition element

Zinc is not classified as a transition element because:

• It has a completely filled $d$-subshell ($3d^{10}$) in its common oxidation state ($+2$).
• Transition elements must have partially filled $d$-orbitals in their common oxidation states.
• Zinc exhibits only one oxidation state ($+2$), whereas transition elements typically show variable oxidation states.

c) Vertical retort and reduction reaction

The vertical retort is used for the extraction of zinc from its ore. The reduction reaction of zinc oxide with coke (carbon) is as follows:

$$\mathrm{ZnO}+\mathrm{C}\stackrel{1200°\mathrm{C}}{\to }\mathrm{Zn}+\mathrm{CO}\uparrow$$

ZnO+C1200°CZn+CO

d) Reaction with air over time

When zinc is exposed to air for a long time, it forms a protective layer of zinc oxide (ZnO) and later zinc carbonate (ZnCO₃) due to the reaction with moisture and carbon dioxide in the air:

Carbon dioxideCarbon dioxide

$$2\mathrm{Zn}+\mathrm{O}{}_2\to 2\mathrm{ZnO}$$ $$\mathrm{ZnO}+\mathrm{CO}{}_2+\mathrm{H}{}_2\mathrm{O}\to \mathrm{ZnCO}{}_3\cdot \mathrm{H}{}_2\mathrm{O}$$

This layer prevents further corrosion, making zinc useful for galvanizing iron.