What is the process of converting sulphide to oxide by burning in presence of excess air known as? 

Roasting 

The correct answer is option 2. Roasting.

The process of converting sulfide ores to oxides by burning in the presence of excess air is known as roasting.

During roasting, the sulfide ore is heated strongly in the presence of excess oxygen (from air). This oxidizing atmosphere facilitates the conversion of sulfide minerals to their respective oxides. The sulfur in the sulfide ore reacts with oxygen to form sulfur dioxide gas \((SO_2)\), while the metal component of the sulfide ore is converted to its oxide form. So, the correct answer is Roasting