How many of the following reactions are roasting?
i) `4FeS_2 + 11O_2 rarr 2Fe_2O_3 + 8SO_2`
ii) `2PbS + 3O_2 rarr 2PbO + 2SO_2`
iii) `HgS + O_3 rarr Hg + SO_2`
(iv) `Al_2O_3.2H_2O rarr Al_2O_3 + 2H_2O`
(v) `ZnCO_3 overset(Delta) rarr 4ZnO + CO_2 uarr`

Answer

4

Explanation

Roasting is heating the ore in presence of `O_2` Reactions i), ii), iii) and iv) can be termed roasting.