UPSC Prelims 2014 Q40: Science & Technology – Energy & Environment
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?
- (a) The oil extracted from seeds is used in the manufacture of biodegradable plastics
- (b) The gum made from its seeds is used in the extraction of shale gas
- (c) The leaf extract of this plant has the properties of anti - histamines
- (d) It is a source of high quality biodiesel
Answer: (b) The gum made from its seeds is used in the extraction of shale gas
Explanation
Cluster bean (Guar)
Guar gum is made from the seeds of the cluster bean.
It thickens water, so it is used in the fracking fluid that extracts shale gas.
| Fact | Detail |
|---|---|
| How it helps | Makes water thick enough to carry sand into rock cracks |
| Top producer | India, about 80 percent of world output |
| Main State | Rajasthan; also Haryana and Gujarat |
| Crop type | A hardy legume of dry areas; fixes nitrogen |
Other uses of guar gum: food thickener (ice cream, sauces), paper, textiles and cosmetics.
The options checked:
| Option | Verdict |
|---|---|
| (a) Oil from seeds for biodegradable plastics | Incorrect |
| (b) Gum from its seeds used in the extraction of shale gas | Correct |
| (c) Leaf extract with anti-histamine properties | Incorrect |
| (d) Source of high quality biodiesel | Incorrect |
Answer: (b) the gum made from its seeds is used in the extraction of shale gas.
Why each option is right or wrong
- (a) Incorrect. Guar is valued for its gum, not for oil to make biodegradable plastics.
- (b) CORRECT. Guar gum from the seeds is used in the extraction of shale gas.
- (c) Incorrect. Its leaf extract is not known for anti-histamine properties.
- (d) Incorrect. Guar is not a source of biodiesel; jatropha is the usual example.
Key point
Guar gum (from cluster bean seeds): thickener in fracking fluid for shale gas; India, mainly Rajasthan, is the largest producer.
Remember
Guar gum = shale gas fracking; Rajasthan grows it.
Common mistakes
- Confusing guar with jatropha, the biodiesel plant.
- Not linking the US shale gas boom to the rise in guar prices.
- Thinking guar is valued for its oil.
Exam tip
Guar = gum. Gum thickens the water used in fracking.
Sources
- Agricultural and Processed Food Products Export Development Authority — Guar gum
- ICAR-Central Arid Zone Research Institute — Cluster bean (guar) cultivation