2010 General Studies, all questions
UPSC Prelims 2010 · General Studies
Question 91: Geography
When you travel in certain parts of India, you will notice red soil. What is the main reason for this colour ?
aAbundance of magnesium
bAccumulated humus
cPresence of ferric oxides
dAbundance of phosphates
AnswerThe answer is (c).
Red soil owes its colour to iron oxides: iron in ferric oxide form is spread through the soil formed from crystalline and metamorphic rocks as they weather in warm regions with moderate rain, for example in Tamil Nadu, Karnataka, Odisha and Chhattisgarh. In hydrated form the iron gives a yellow tint. Humus makes soil dark, not red. Remember: red colour = ferric oxide.
Why each option is right or wrong
- (a) Magnesium does not give soil its red colour.
- (b) Humus darkens soil; it does not make it red.
- (c) Right: ferric oxides give the red colour.
- (d) Phosphates do not give soil its red colour.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2010, General Studies, Series A. The paper on upsc.gov.in.