UPSC Prelims 2025 Answer Key PDF: GS & CSAT Solutions

The UPSC Prelims 2025 was successfully held today, May 25, 2025, across various exam centers in India. Lakhs of aspirants appeared for the UPSC Civil Services Preliminary Examination, which is the gateway to prestigious services like IAS, IPS, and IFS.

UPSC Prelims GS & CSAT Answer Keys Released — Image from PTI

With the exam concluded candidates are now looking for ways to analyze their performance. While the official UPSC answer key 2025 will be released after the final stage of the selection process, several top coaching institutes have already shared their unofficial answer keys for both General Studies (GS Paper 1) and CSAT (Paper 2).

Here are the questions, options, and answers for General Studies (GS Paper 1):

1. Consider the following types of vehicles :

I. Full battery electric vehicles
II. Hydrogen fuel cell vehicles
III. Fuel Cell electric hybrid vehicles
How many of the above are considered as alternative powertrain vehicles?
(a) Only one
(b) Only two
(c) All the three
(d) None

Answer: (c) All the three

2. With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements:

I. All types of UAVs can do vertical landing.
II. All types of UAVs can do automated hovering.
III. All types of UAVs can use battery only as a source of power supply.
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All the three
(d) None

Answer: (d) None

3. In the context of electric vehicle batteries, consider the following elements:

I. Cobalt
II. Graphite
III. Lithium
IV. Nickel
How many of the above usually make up battery cathodes?
(a) Only one
(b) Only two
(c) Only three
(d) All the four

Answer: (c) Only three (Cobalt, Lithium, and Nickel are typically used in battery cathodes. Graphite is primarily used in the anode.)

4. Consider the following:

I. Cigarette butts
II. Eyeglass lenses
III. Car tyres
How many of them contain plastic?
(a) Only one
(b) Only two
(c) All the three
(d) None

Answer: (c) All the three

5. Consider the following substances:

I. Ethanol
II. Nitroglycerine
III. Urea
Coal gasification technology can be used in the production of how many of them?
(a) Only one
(b) Only two
(c) All the three
(d) None

Answer: (c) All the three

6. What is the common characteristic of the chemical substances generally known as CL-20, HMX and LLM-105, which are sometimes talked about in media?

(a) These are alternatives to hydro-fluorocarbon refrigerants
(b) These are explosives in military weapons
(c) These are high-energy fuels for cruise missiles
(d) These are fuels for rocket propulsion

Answer: (b) These are explosives in military weapons

7. Consider the following statements:

I. It is expected that Majorana 1 chip will enable quantum computing.
II. Majorana 1 chip has been introduced by Amazon Web Services (AWS).
III. Deep learning is a subset of machine learning.
Which of the statements given above are correct?
(a) I and II only
(b) II and III only
(c) I and III only
(d) I, II and III

Answer: (c) I and III only (Majorana 1 chip is associated with Microsoft, not AWS).

8. With reference to monoclonal antibodies, often mentioned in news, consider the following statements :

I. They are man-made proteins.
II. They stimulate immunological function due to their ability to bind to specific antigens.
III. They are used in treating viral infections like that of Nipah virus.
Which of the statements given above are correct?
(a) I and II only
(b) II and III only
(c) I and III only
(d) I, II and III

Answer: (d) I, II and III

9. Consider the following statements:

I. No virus can survive in ocean waters.
II. No virus can infect bacteria.
III. No virus can change the cellular transcriptional activity in host cells.
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All the three
(d) None

Answer: (d) None

10. Consider the following statements:

Statement I: Activated carbon is a good and an attractive tool to remove pollutants from effluent streams and to remediate contaminants from various industries.
Statement II: Activated carbon exhibits a large surface area and a strong potential for adsorbing heavy metals.
Statement III: Activated carbon can be easily synthesized from environmental wastes with high carbon content.
Which one of the following is correct in respect of the above statements?
(a) Both Statement II and Statement III are correct and both of them explain Statement I
(b) Both Statement II and Statement III are correct but only one of them explains Statement I
(c) Only one of the Statements II and III is correct and that explains Statement I
(d) Neither Statement II nor Statement III is correct

Answer: (a) Both Statement II and Statement III are correct and both of them explain Statement I

For complete access of UPSC Prelims 2025 Answer Key - General Studies (GS Paper 1)

Download UPSC Prelims 2025 Answer Key PDF:

GS Paper 1 Answer Key - [Download Link]

CSAT Paper 2 Answer Key - [Download Link]

These answer keys help candidates estimate their scores and predict the expected cut-off marks for UPSC Prelims 2025.

UPSC Prelims 2025 GS Paper 1 Answer Key

UPSC Prelims 2025 GS Paper 2 Answer Key

Coming Soon: Detailed UPSC Prelims 2025 Answer Keys with Explanations

Stay tuned as we're about to release the complete UPSC Prelims 2025 Answer Keys. These will feature detailed explanations for each question to help you grasp the logic behind every correct answer. Along with this, we'll share a thorough analysis of this year's Prelims exam, uncovering key trends, difficulty levels, and insights that can guide your future UPSC preparation strategy.

How to Download UPSC Prelims Official Answer Key (When Released)

The official UPSC Prelims Answer Key 2025 will be released by the Union Public Service Commission on its official website after the final results of the exam cycle (Post Interviews). Here's how to access it when available:

Steps to Download:

Visit the official UPSC website - https://upsc.gov.in
Click on the 'Examination' tab in the menu.
Choose 'Answer Keys' from the dropdown.
Look for 'Civil Services Preliminary Examination 2025'
Click on the link and download the GS & CSAT answer key PDFs.

UPSC Prelims 2025 Marking Scheme

Understanding the marking pattern will help you estimate your final scores:

General Studies Paper I:

100 questions | 2 marks each
0.66 negative marks for each wrong answer

CSAT Paper II:

80 questions | 2.5 marks each
0.83 negative marks per incorrect answer
CSAT is qualifying: 33% required to clear

Why Use the Unofficial Answer Key?

Quick score estimation without waiting for official keys
Helps decide whether to start preparing for Mains
Compare accuracy across answer sets from different institutes
Identifies controversial questions or possible wrong answers

Important Note

While unofficial answer keys are useful, candidates should not consider them final. Minor discrepancies may exist. The UPSC's official key is the only legally accepted version and forms the basis for final result calculation.