Question

Give the name and formula of an ore of zinc.
(a) Roasting of the ore.
(b) Reduction of the zinc compound which is the product of the above reaction.
(c) What in addition to a zinc compound, is put into the furnace? State one large scale use of zinc.

Answer 1

One example of an ore of zinc is zinc blende and its formula is ZnS.

(a) Roasting of the ore – Zinc blende is roasted in the presence of the air and converted to zinc oxide.

$$\begin{gathered} 2\mathrm{ZnS}+3{\mathrm{O}}_2\stackrel{\mathrm{H}\mathrm{eat}}{\to }2\mathrm{ZnO}+2{\mathrm{SO}}_2 \\ \mathrm{Zinc}\mathrm{blende}\mathrm{Zinc}\mathrm{oxide} \end{gathered}$$

(b) On heating, zinc oxide is reduced to zinc metal, with carbon (coke) as a reducing agent.

$$\begin{gathered} \mathrm{ZnO}+C\stackrel{\mathrm{h}\mathrm{eat}}{\to }\mathrm{Zn}+\mathrm{CO} \\ \mathrm{Zinc}\mathrm{oxide}\mathrm{Zinc} \end{gathered}$$

(c) Along with zinc compound, coke (carbon) is added into the furnace.
Disclaimer: Any one of the following uses of zinc can be used to answer the given question.
Zinc is used:
1. for producing useful alloys like brass, german silver, etc. These alloys are used in automobiles and for the manufacture of household and office articles.
2. for making containers of dry cells.
3. in manufacture of paints, antiseptics, preservatives etc.
4. in galvanisation of iron and steel articles.
5. in extraction of silver and gold by displacing them from their salts.
6. as reducing agent in preparation of synthetic perfumes and drugs.