Explain the following: (a) CO_2 is a better reducing agent below 710 K whereas CO is a better reducing agent above 710 K. (b) Generally sulphide ores are converted into oxides before reduction. (c) Silica is added to the sulphide ore of copper in the reverberatory furnace. (d) Carbon and hydrogen are not used as reducing agents at high temperatures. (e) Vapour phase refining method is used for the purification of Ti.

Explain the following: (a) CO_2 is a better reducing agent below 710

1.	Explain the following: (a) CO_2 is a better reducing agent below 710 K whereas CO is a better reducing agent above 710 K. (b) Generally sulphide ores are converted into oxides before reduction. (c) Silica is added to the sulphide ore of copper in the reverberatory furnace. (d) Carbon and hydrogen are not used as reducing agents at high temperatures. (e) Vapour phase refining method is used for the purification of Ti.
Answer» Solution :(a) At temperature below 710 K, `Delta_fG_((C","CO_2))^(Theta) < Delta_fG_((C","CO))^(Theta)` Hence, `CO_2` is better reducing agent below 710 K. At temperature above 710 K, `Delta_(F)G_(C","CO)^(Theta) < Delta_(f)G_((C","CO_2)^(Theta)` Hence, CO is better reducing agent above 710 K. (e) Ti reacts with iodine to form `Til_4`, which decomposes to `Ti` at HIGH temperature to give extra PURE `Ti`. `underset("(impure)")(Ti) + 2I_2 to Til_4 overset(1800K)(rarr)underset("(pure)")(Ti) + 2I_2`