2010 General Studies, all questions

UPSC Prelims 2010 · General Studies

Question 63: Economy and Social Development

Given below are the names of four energy crops. Which one of them can be cultivated for ethanol ?

aJatropha
bMaize
cPongamia
dSunflower

AnswerThe answer is (b).

Ethanol is made by fermenting sugars or starch, so crops such as sugarcane (molasses), maize, sorghum and sugar beet are the feedstocks. Maize starch is converted to sugar and then fermented to ethanol. Jatropha and Pongamia yield non-edible oils and sunflower yields edible oil; these oils are used for biodiesel, not ethanol. Remember: ethanol from sugar or starch crops (blended with petrol); biodiesel from oil-bearing seeds.

Why each option is right or wrong
  • (a) Jatropha gives non-edible oil for biodiesel.
  • (b) Right: maize starch ferments to ethanol.
  • (c) Pongamia gives non-edible oil for biodiesel.
  • (d) Sunflower gives oil, used as food or biodiesel, not ethanol.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2010, General Studies, Series A. The paper on upsc.gov.in.