Q131. The property of metals by which they can be beaten into thin sheets is known as:
Science and Technology: RAS Prelims MCQs
1113 RAS Prelims practice MCQs on science and technology are on this page, in 6 chapters. They cover the basics of everyday science, computers and information technology, defence and space technology in India, genetics, biotechnology and nanotechnology, science and technology policies and government programmes, and recent advances with Indian contributors and indigenisation. Each question has an answer and an explanation.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
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Q132. Which of the following metals exists as a liquid at room temperature?
Explanation
Mercury is a unique chemical element that is classified as a metal but remains in a liquid state at standard room temperature and pressure. This behavior is due to its unique electronic configuration, which results in weak bonding between its atoms. Because it is a liquid and a good conductor, it has been widely used in thermometers, barometers, and various electrical switches.
Q133. Identify the only non-metal that exists as a liquid at room temperature.
Explanation
Most non-metals are either gases or solids at room temperature. Bromine is the only non-metallic element that exists as a liquid under standard conditions. It is a reddish-brown, volatile liquid with a sharp, unpleasant odor. Belonging to the halogen group, bromine is highly reactive and is commonly used in flame retardants, water treatment chemicals, and as a reagent in organic synthesis.
Q134. Consider the following statements about the reactivity series of metals:
I. Metals at the top of the series can displace metals below them from their salt solutions.
II. Gold and platinum are placed at the bottom of the series.
III. Metals below hydrogen in the series can easily liberate hydrogen gas from dilute acids.
Which of the above statement(s) is/are correct?
I. Metals at the top of the series can displace metals below them from their salt solutions.
II. Gold and platinum are placed at the bottom of the series.
III. Metals below hydrogen in the series can easily liberate hydrogen gas from dilute acids.
Which of the above statement(s) is/are correct?
Explanation
In the reactivity series, more reactive metals can displace less reactive ones from their compounds. Highly unreactive metals like gold and platinum are found at the bottom. However, only metals placed above hydrogen in the series are capable of displacing hydrogen from dilute acids to release gas. Metals below hydrogen, such as copper and silver, do not react in this way.
Q135. Metal oxides that exhibit both acidic and basic behaviors are known as:
Explanation
Amphoteric oxides are metallic oxides that show both acidic and basic characteristics. They can react with both acids and bases to produce salt and water. Common examples include aluminum oxide and zinc oxide. This dual reactivity is important in chemistry for identifying specific metal ions and is utilized in industrial processes where pH control and chemical neutralization are necessary for various reactions.
Q136. The process of heating carbonate ores strongly in limited air to convert them into oxides is termed:
Explanation
Calcination is a metallurgical process where carbonate ores are heated strongly in the absence or limited supply of air. This thermal treatment causes the ore to decompose, releasing carbon dioxide gas and leaving behind the metal oxide. This step is essential for preparing the ore for the subsequent reduction process, which eventually extracts the pure metal from its naturally occurring form.
Q137. Anodizing is a process of forming a thick oxide layer to prevent corrosion on which of the following metals?
Explanation
Anodizing is an electrochemical process used to increase the thickness of the natural oxide layer on the surface of aluminum parts. This thick, protective coating improves corrosion resistance, increases surface hardness, and allows for the application of dyes for decorative purposes. Unlike iron, which rusts when oxidized, the aluminum oxide layer is stable and adheres strongly to the metal, protecting it further.
Q138. Galvanization is a method of protecting steel and iron from rusting by coating them with a thin layer of:
Explanation
Galvanization is a widely used method for protecting iron and steel from atmospheric corrosion or rusting. It involves applying a thin, protective coating of zinc over the metal surface. Zinc acts as a sacrificial barrier; even if the coating is scratched, the zinc will corrode in preference to the underlying iron, effectively extending the lifespan of structural components and various hardware.
Q139. The most abundant metal in the Earth’s crust by weight is:
Explanation
Aluminum is the most abundant metallic element found in the Earth’s crust, making up approximately eight percent of its total weight. While it is extremely common, it is never found in its pure metallic form in nature; instead, it occurs in various minerals, most notably bauxite. Due to its abundance, lightweight, and corrosion resistance, it is a critical material for modern industry.
Q140. Arrange the following metals in decreasing order of their chemical reactivity:
I. Calcium
II. Potassium
III. Magnesium
IV. Sodium
Which of the following is the correct order?
I. Calcium
II. Potassium
III. Magnesium
IV. Sodium
Which of the following is the correct order?
Explanation
The reactivity of metals determines how easily they lose electrons to form positive ions. Potassium is the most reactive of the group, followed by sodium and then calcium. Magnesium is the least reactive among these four. Therefore, the correct sequence in decreasing order of their chemical reactivity is potassium, then sodium, followed by calcium, and finally magnesium at the end.Answer key for these questions
| Q | Correct answer |
|---|---|
| 131 | (c) Malleability |
| 132 | (d) Mercury |
| 133 | (c) Bromine |
| 134 | (a) I and II only |
| 135 | (d) Amphoteric oxides |
| 136 | (a) Calcination |
| 137 | (c) Aluminum |
| 138 | (a) Zinc |
| 139 | (d) Aluminum |
| 140 | (a) II, IV, I, III |
Key facts from Science and Technology
- The RPSC paper is General Knowledge and General Science, so science questions come with a strong dose of applied and recent topics.
- Everyday science questions test the laws and terms of physics, chemistry and biology through examples.
- Defence and space questions pair a missile, satellite or mission with its year and organisation.
- Policy questions ask for the year, the body and the aim of schemes like STIP, the National Quantum Mission and BioE3.
- Health, environment and agriculture are on a separate page, with their own chapters.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Science and Technology?
This page has 1113 practice MCQs on Science and Technology. Each has the correct answer, and most have an explanation.
Which chapters does the science and technology set cover?
Six chapters: basics of everyday science; computers, information and communication technology; defence and space technology in India; genetics, biotechnology and nanotechnology; science and technology policies and government programmes; and recent advances, Indian contributors and indigenisation.
Is science and technology part of the RAS Prelims syllabus?
Yes. The RPSC paper is called General Knowledge and General Science, and its syllabus lists science and technology topics along with environment, health, agriculture and government programmes, so questions can come from any of these areas.
How should I prepare science for RAS Prelims?
Revise the concepts by examples, then learn the missions, schemes and scientists with their year and organisation. Attempt each chapter, read the explanations and keep a list of the facts you missed.