Question

UPSC Prelims 2014 Question:

Which of the following is/are the example/examples of chemical change?

  1. Crystallization of sodium chloride 
  2. Melting of ice 
  3. Souring of milk

Select the correct answer using the code given below:

  1. 1. 1 and 2 only
  2. 2. 3 only
  3. 3. 1, 2 and 3
  4. 4. None

Answer (Detailed Solution Below)

Option 2: 3 only

Detailed Solution

Explanation:

  • A chemical change is a process in which one or more substances are altered into one or more new and different substances. In other words, a chemical change is a chemical reaction involving the rearrangement of atoms.

  • While a physical change can often be reversed, a chemical change typically cannot be, except through more chemical reactions. Crystallization of sodium chloride and melting of ice can be reversed, hence these are physical changes. So, point 1 and 2 are not correct.

  • Souring of milk involves change of atoms, and typically cannot be reversed. Which is why it's a chemical change. So, point 3 is correct.

Therefore, option (2) is the correct answer. 

Subject: Science & Technology | Chemistry

Latest UPSC Exam 2026 Updates

Last updated on February, 2026

UPSC Notification 2026 is now out on the official website at upsconline.nic.in.

UPSC IFoS Notification 2026 is now out on the official website at upsconline.nic.in.

UPSC Calendar 2026 has been released.

→ Check out the latest UPSC Syllabus 2026 here.

→ Join Vajiram & Ravi’s Interview Guidance Programme for expert help to crack your final UPSC stage.

UPSC Mains Result 2025 is now out.

UPSC Prelims 2026 will be conducted on 24th May, 2026 & UPSC Mains 2026 will be conducted on 21st August 2026.

→ The UPSC Selection Process is of 3 stages-Prelims, Mains and Interview.

→ Prepare effectively with Vajiram & Ravi’s UPSC Prelims Test Series 2026 featuring full-length mock tests, detailed solutions, and performance analysis.

→ Enroll in Vajiram & Ravi’s UPSC Mains Test Series 2026 for structured answer writing practice, expert evaluation, and exam-oriented feedback.

→ Join Vajiram & Ravi’s Best UPSC Mentorship Program for personalized guidance, strategy planning, and one-to-one support from experienced mentors.

UPSC Result 2024 is released with latest UPSC Marksheet 2024. Check Now!

UPSC Toppers List 2024 is released now. Shakti Dubey is UPSC AIR 1 2024 Topper.

→ Also check Best UPSC Coaching in India

Vajiram Content Team
Vajiram Content Team
UPSC GS Course 2026
UPSC GS Course 2026
₹1,75,000
Enroll Now
GS Foundation Course 2 Yrs
GS Foundation Course 2 Yrs
₹2,45,000
Enroll Now
UPSC Mentorship Program
UPSC Mentorship Program
₹85000
Enroll Now
UPSC Sureshot Mains Test Series
UPSC Sureshot Mains Test Series
₹19000
Enroll Now
Prelims Powerup Test Series
Prelims Powerup Test Series
₹8500
Enroll Now
Enquire Now