Q181. Red and yellow soils in Rajasthan are predominantly concentrated in the districts of:
Rajasthan Geography: RAS Prelims MCQs
529 RAS Prelims practice MCQs on the geography of Rajasthan are on this page, in 13 chapters. They cover location, extent and physiography, rivers and lakes, climate, natural vegetation and wildlife, soils, agriculture, livestock, irrigation, minerals, population, urbanisation, tribes and tourism. Each question has an answer and an explanation, in the formats the exam uses.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
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Q182. Given below are two statements, one labelled as
Assertion (A) and the other labelled as Reason (R):
Assertion (A): Certain soils in the transitional plains of Sawai Madhopur and Bhilwara display a distinct yellow color.
Reason (R): Ferric oxides present in these soils undergo a process of hydration in regions of intermediate rainfall. In the context of the above statements, which one of the following is correct?
Assertion (A) and the other labelled as Reason (R):
Assertion (A): Certain soils in the transitional plains of Sawai Madhopur and Bhilwara display a distinct yellow color.
Reason (R): Ferric oxides present in these soils undergo a process of hydration in regions of intermediate rainfall. In the context of the above statements, which one of the following is correct?
Explanation
The distinct yellow color observed in the soils of Sawai Madhopur and Bhilwara is a result of chemical processes acting on iron minerals. When ferric oxides present in the soil undergo hydration under conditions of intermediate rainfall, they transition from red to yellow. This pedogenic process is common in regions where moisture levels are sufficient to cause hydration but not leaching.
Q183. The characteristic red color of the red loam soils found in southern Rajasthan is most appropriately attributed to:
Explanation
Red loam soils in southern Rajasthan derive their characteristic color from the diffusion of iron minerals found in the underlying crystalline and metamorphic rocks. As these rocks weather, iron is released and oxidized, spreading through the soil mass. This process gives the soil its reddish hue, which is distinct from the colors caused by organic matter accumulation or wind-blown sand deposits.
Q184. Match the soil colours (List I) with their primary causative chemical compounds or conditions (List II):
| Soil Colours | Causative Factor |
|---|---|
| A. Deep Black | i. Hydration of iron oxides |
| B. Red | ii. Accumulation of surface salts |
| C. Yellow | iii. Unhydrated ferric oxides |
| D. White/Grey patches | iv. Titaniferous magnetite and clay-humus complex |
Explanation
Soil colors are determined by specific chemical compounds and environmental conditions. Deep black color arises from titaniferous magnetite and clay-humus complexes. Red is caused by unhydrated ferric oxides, whereas yellow results from the hydration of those oxides. White or grey patches on the surface indicate the accumulation of soluble salts, often seen in saline soils due to upward capillary action.
Q185. A farmer in Banswara district is planning his Kharif sowing on well-drained red loam soil. Based on the soil properties, which of the following crops is most conceptually suited and traditionally cultivated in this region?
Explanation
Red loam soils, predominantly found in the Banswara district of southern Rajasthan, are well-drained and suitable for specific crops. Maize is conceptually and traditionally the most suited crop for this region due to the soil’s moisture characteristics and the local climate. While other crops are grown elsewhere, maize remains a staple and a primary Kharif crop in these red-loamed areas.
Q186. Black (Regur) soils in Rajasthan are predominantly found in the:
Explanation
Black soils, also known as Regur soils, are predominantly found in the south-eastern part of Rajasthan, specifically within the Hadoti region. This area includes districts like Kota, Bundi, Baran, and Jhalawar.
Q187. Which of the following statements about the Black soils of the Hadoti region is incorrect?
Explanation
The black soils of the Hadoti region are formed from volcanic basaltic rocks and are rich in calcium carbonate and potash. One of their most significant characteristics is their exceptionally high water-holding capacity, which reduces the frequency of irrigation needed compared to sandy soils. They also exhibit self-ploughing behavior as they shrink and swell, creating deep and characteristic vertical cracks.
Q188. Consider the following soil textural classes found in Rajasthan:
I. Clayey soil
II. Sandy soil
III. Silty soil
IV. Loamy soil
Arrange the above classes in the increasing order of their inherent water retention capacity:
I. Clayey soil
II. Sandy soil
III. Silty soil
IV. Loamy soil
Arrange the above classes in the increasing order of their inherent water retention capacity:
Explanation
The water retention capacity of soil is primarily determined by its texture and pore space. Sandy soils have the lowest retention due to large pores. Loamy soils have intermediate retention, followed by silty soils. Clayey soils, characterized by very fine particles and small pores, possess the highest inherent capacity to hold water, making them the most moisture-retentive among all classes.
Q189. The characteristic shrink-swell behavior of the black soils in the Kota and Bundi districts is primarily due to the dominance of which clay mineral?
Explanation
The shrink-swell behavior characteristic of black soils in Kota and Bundi is caused by the dominance of the montmorillonite clay mineral. This specific type of silicate clay has a lattice structure that expands when water enters the layers and contracts upon drying. This mineralogical property is responsible for the deep cracks and the high plasticity observed in these heavy soils.
Q190. Which of the following pairs of soil type and its highly suitable commercial crop in Rajasthan is incorrectly matched?
Explanation
While black soils are excellent for cotton and soybean, and desert sandy soils support hardy crops like moth bean, the pairing of red loam soil with sugarcane is traditionally incorrect for Rajasthan. Red loams in the south are better suited for maize. Sugarcane typically requires deeper, more fertile alluvial or heavy soils with very high water availability and nutrient levels.Answer key for these questions
| Q | Correct answer |
|---|---|
| 181 | (b) Sawai Madhopur, Bhilwara, and Ajmer |
| 182 | (a) Both A and R are true and R is the correct explanation of A. |
| 183 | (a) The diffusion of iron in crystalline and metamorphic rocks |
| 184 | (a) A-iv, B-iii, C-i, D-ii |
| 185 | (a) Maize |
| 186 | (d) Hadoti region |
| 187 | (c) Highly frequent irrigation needed due to low water retention |
| 188 | (a) II, IV, III, I |
| 189 | (a) Montmorillonite |
| 190 | (b) Red Loam Soil - Sugarcane |
Key facts from Rajasthan Geography
- The RPSC syllabus lists Rajasthan’s location, extent and physiography, rivers and lakes, climate, vegetation, biodiversity, soils, agriculture, livestock, irrigation, population, urbanisation and tribes.
- Many questions ask for a number or a name: the area of the State, a district’s density, the length of a canal, the home district of a mine.
- Rajasthan is the biggest State of India by area, and several chapters test the contrast between the arid west and the humid south-east.
- Minerals, irrigation and wildlife are the chapters with the most name-based questions, so keep a list of districts and projects.
- Population questions use Census 2011 figures.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Rajasthan Geography?
This page has 529 practice MCQs on Rajasthan Geography. Each has the correct answer, and most have an explanation.
Which chapters does the Rajasthan geography set cover?
Thirteen chapters: location, extent and physiography; rivers and lakes; climate; natural vegetation, biodiversity and conservation; soils; agriculture; livestock and animal husbandry; irrigation; minerals; population; urbanisation; tribes; and tourism.
Is Rajasthan geography in the RAS Prelims syllabus?
Yes. RPSC lists Geography of Rajasthan as a separate part of the syllabus, including location, rivers, climate, vegetation, soil, agriculture, livestock, irrigation, population, urbanisation and tribes, after the world and India sections.
How can I prepare Rajasthan geography quickly?
Keep a Rajasthan map and mark every river, dam, mine, sanctuary and fair that appears. Attempt each chapter, read the explanations and revise the numbers: area, population, density and canal lengths.