VOLCANIC eruptions are heart stopping at their extreme but this volcano of Indonesia looks spectacular when it flows out its lava. The volcano called Kawah Ijen, erupts striking blue lava and is therefore also known as blue volcano. The alive Kawah Ijen volcano is 8,660 ft tall. It is one of the world's most unique volcanoes because instead of producing the usual red lava and black smoke, its underground activities result in bright blue flames rising into the air. The phenomenon is caused due to the combustion of the volcano’s sulphuric gases with atmospheric oxygen at temperatures above 360°C. The blue volcano spews out extremely high quantities of sulphuric gases at high pressure and temperatures sometimes even at 600°C along with the lava. But the colour of this blue molten lava can be seen only during night time. 

At the top of the volcano, Kawah Ijen Crater Lake is the world's largest body of water filled with hydrochloric acid. Indeed, it's the acid that makes the water green. The volcano spews hydrogen chloride gas, which reacts with the water and forms a highly condensed hydrochloric acid with a pH of almost 0. The lake has a volume of 36 million cubic meters.This sulphur-rich lava has led to mineral deposition around the volcano. Miners extract the sulfur rock, which is formed after the blue flames blow out leaving behind a solid sulfur-rich rock. They then carry these large rocks in baskets down the side of the mountain to be paid per kilogram. The work is uncontrolled and small children can often be seen doing labour hoping to support their families’ low incomes with additional money. They usually take two trips daily. Each local worker is paid about 680 Indonesian rupiahs per kilogram. The workers are exposed to toxic sulphur gases for prolonged periods of time. The conditions are highly hazardous for health. The sulphur that is collected is considered among the purest in Indonesia, and is destined for the food and chemical industry.

Answer the following questions based on above passage. 

Q-1:Which volcano called kawah ljen?

Q-2: Why kawah ljen is one of the world's most unique volcanoes ?

Q-3: Why this phenomenon of blue volcano caused ?

Q-4: Why sulphur is collected from miner extracts by workers ?

Q-5: What the blue volcano spewed out and when they can be seen ?