Sulphur Dioxide:

Sulphur dioxide (molecular weight 64) is a suffocating, colourless and irritating gas and is double as heavy as air at atmospheric conditions. This was mainly used as a household refrigerant in the older days, but has been refused for better refrigerants. It suffers from many disadvantages. Sulphur dioxide reacts along water producing sulphurous acid, which in presence of oxygen convert in sulphuric acid, a corrosive compound for metals. This is non-flammable however attacks foodstuff on coming in contact along it. This is also partially miscible along the lubricating oil.