Q591. What primary geographical factor caused the early Chalcolithic settlements to densely cluster in the Mewar region?
RAS Prelims MCQ Practice
9,654 RAS Prelims practice MCQs with the correct answer and a clear explanation for each. Filter by subject and chapter.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
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Q592. Which acid is naturally present in sour milk or curd?
Explanation
Lactic acid is the organic acid naturally present in sour milk, curd, and yogurt. It is produced when certain bacteria, such as Lactobacillus, ferment the lactose sugar found in milk. This fermentation process increases the acidity of the milk, causing the proteins to coagulate and giving curd its characteristic tangy flavor and thick texture, while also acting as a natural preservative.
Q593. Painted rock shelters representing prehistoric art in Rajasthan are prominently concentrated in the districts associated with which river valley?
Explanation
Painted rock shelters representing prehistoric art in Rajasthan are most prominently concentrated in the Chambal river valley, particularly within the Kota and Bundi districts. These shelters feature vibrant depictions of animals, hunting scenes, and human figures, providing a rare glimpse into the symbolic world of ancient hunter-gatherer communities. The rugged landscape of the valley provided the necessary outcrops for these expressions.
Q594. The sting of ants and bees contains which of the following acids, causing pain and irritation?
Explanation
When ants or bees sting, they inject a small amount of formic acid, also known as methanoic acid, into the skin. This chemical is responsible for the sharp pain, redness, and swelling associated with the bite. Because it is an acid, its effects can sometimes be neutralized by applying a mild base, such as baking soda paste, which helps to alleviate the irritation.
Q595. Observing the spatial transition of ancient cultures in Rajasthan, the trajectory of major development from the Palaeolithic era to the mature Chalcolithic era generally reflects a movement toward:
Explanation
The long-term trajectory of ancient development in Rajasthan shows a clear movement toward river valleys in the south and east. While early Palaeolithic groups were more widely dispersed, the transition to a settled Chalcolithic lifestyle required more stable resources. The fertile soil and perennial water of the Banas and Chambal systems offered the necessary conditions for large-scale agriculture and permanent settlements.
Q596. Rainwater is typically considered "acid rain" when its pH drops below approximately:
Explanation
Normal rainwater is slightly acidic, with a pH of about five point six, due to dissolved carbon dioxide forming weak carbonic acid. However, when the pH drops below this level, it is classified as acid rain. This increased acidity is primarily caused by sulfur dioxide and nitrogen oxides from industrial activities reacting with water vapor in the atmosphere to form stronger acids.
Q597. Which of the following pairings of an ancient site and its modern district in Rajasthan is the odd one out?
Explanation
Identifying the correct location of archaeological sites is essential for understanding regional history. While Kalibangan is in Hanumangarh, Bagor is in Bhilwara, and Ganeshwar is in the Sikar region, the pairing of Ahar with Bikaner is incorrect. Ahar is the type site of the Banas culture and is located in the Udaipur district. Bikaner belongs to a different geographical and archaeological context altogether.
Q598. Which of the following salts is formed when a strong acid reacts with a weak base?
Explanation
When a strong acid reacts with a weak base, the resulting salt is classified as an acidic salt. This occurs because the strong acid provides more hydrogen ions than the weak base can effectively neutralize. When such a salt is dissolved in water, it undergoes partial hydrolysis, releasing excess hydrogen ions and resulting in a solution with a pH value of less than seven.
Q599. The unique ability of carbon atoms to form long chains or rings by bonding with each other is known as:
Explanation
Catenation is the unique ability of carbon atoms to form stable covalent bonds with one another, resulting in long chains, branched structures, or closed rings. This property is due to carbon’s small atomic size and the significant strength of the carbon-carbon bond. Catenation is the fundamental reason for the vast diversity and complexity of organic molecules, which form the basis of life.
Q600. Given below are two statements: one is labelled as Assertion (A) and the other is labelled as
Reason (R).
Assertion (A): Graphite is a good conductor of electricity, whereas diamond is not.
Reason (R): In graphite, each carbon atom has one free, delocalized electron, whereas in diamond, all four valence electrons are used in covalent bonding.
Reason (R).
Assertion (A): Graphite is a good conductor of electricity, whereas diamond is not.
Reason (R): In graphite, each carbon atom has one free, delocalized electron, whereas in diamond, all four valence electrons are used in covalent bonding.
Explanation
Graphite and diamond are allotropes of carbon with different structures. In diamond, each carbon atom is covalently bonded to four others in a rigid tetrahedron, leaving no free electrons. In graphite, each atom is bonded to only three others in layers, leaving one delocalized electron per atom. These free electrons are mobile, allowing graphite to conduct electricity, whereas diamond remains an insulator.Answer key for these questions
| Q | Correct answer |
|---|---|
| 591 | (c) The region possessed fertile river valleys and proximity to rich copper deposits in the Aravallis |
| 592 | (c) Lactic acid |
| 593 | (b) Chambal valley (Kota, Bundi) |
| 594 | (b) Formic (Methanoic) acid |
| 595 | (d) River valleys providing perennial water and fertile soil in the south and east |
| 596 | (c) 5.6 |
| 597 | (a) Ahar - Bikaner |
| 598 | (c) Acidic salt |
| 599 | (c) Catenation |
| 600 | (a) Both A and R are true and R is the correct explanation of A. |
Frequently asked questions
How many RAS Prelims practice MCQs are there on RAS Prelims?
This page has 9654 practice MCQs on the RAS Prelims syllabus. Each has the correct answer, and most have an explanation.
How should I practise MCQs for RAS Prelims?
Attempt each question first, then open the answer and read the explanation. Practise one chapter at a time, note the facts you got wrong and revise them. Repeat the chapter after a few days.
Are these actual RAS Prelims past-paper questions?
No. These are practice questions written for the RAS Prelims syllabus. They follow the pattern the exam uses: factual questions, statement-based questions, match-the-list and assertion-reason.