Olive oil regulation and adulteration phenolphthalein as a pH indicator dye. The base stock solution was titrated to neutralize an equal quantity of the acid, so without the presence of vegetable oil it would require 40 milliliters of acid to cause a color change, but in the pure oils tested (almond, benne, cottonseed, cod liver oil, linseed oil, and olive oil, only 6 milliliters were required. In accordance with this, olive oil adulterated with 10% mineral oil required 8 milliliters, and with 20% 11 milliliters. The adulterated oil tested in 1887 required 14 to 17 milliliters to neutralize, so it might have been 30-40% mineral
Narva Oil Plant shale per year. It would produce 290,000 tonnes of shale oil and 75 million cubic meters of oil shale gas per year. The cost of the new oil plant is approximately 3 billion Estonian kroons (€191.7 million, US$264.2 million). The construction was launched in the second half of 2009, and the new Enefit280 plant was commissioned in 2012. The first barrel of shale oil was produced in the new plant on 20 December 2012. Narva Oil Plant Narva Oil Plant (), a subsidiary of Eesti Energia, is a producer of shale oil from oil shale. It operates a commercial scale