UPSC Prelims 2014 · Question 20 of 100

UPSC Prelims 2014 question on Guar Gum Shale Gas

In India, cluster bean (Guar) is traditionally used as a vegetable or animal feed, but recently the cultivation of this has assumed significance. Which one of the following statements is correct in this context?

  1. The oil extracted from its seeds is used in the manufacture of biodegradable plastics.
  2. The gum made from its seeds is used in the extraction of shale gas.
  3. The leaf extract of this plant has the properties of anti-histamines.
  4. It is a source of high quality biodiesel.
Show answer

Answer: B. The gum made from its seeds is used in the extraction of shale gas.

Verdict

The answer is that the gum made from its seeds is used in the extraction of shale gas. Guar gum is a hydraulic fracturing input, which is why cluster bean cultivation suddenly gained value.

Analysis

Guar gum is a galactomannan that thickens water dramatically at low concentration, and fracturing fluid needs exactly that property to carry proppant sand into the fractured rock. The American shale boom therefore drove a sharp rise in Indian guar exports and prices. The biodegradable plastics option is wrong because guar's industrial value lies in the seed gum, not in a seed oil. The anti histamine option attaches a pharmacological property to the leaf that is not the reason for the crop's new significance. The biodiesel option is wrong because cluster bean is not an oilseed of that class.

Source

The Hindu, Indian Express and Science Reporter coverage of the guar and shale gas link.

How to crack it

The stem itself carries the clue. Recently assumed significance signals that a news event, not a traditional use, is being tested, so discard options describing ordinary agronomic or medicinal properties. Then ask which global story around 2012 to 2014 could lift an Indian bean, and shale gas is the only candidate. Reading the stem for the words recently or in news and letting them steer you toward the current affairs option is a reusable move.

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