Yes, there are mock tests available that simulate the previous years' papers of UPSC Chemistry optional. These mock tests are designed to help candidates prepare for the Chemistry optional paper in the UPSC examination. Here are some details about these mock tests:

1. EduRev:
- EduRev is a platform that provides a wide range of educational resources, including mock tests for various competitive exams.
- They offer mock tests specifically designed for the UPSC Chemistry optional paper.
- These mock tests are created by experts in the field and aim to simulate the pattern and difficulty level of the previous years' papers.
- The tests cover all the important topics and concepts from the Chemistry optional syllabus.

2. Simulated Previous Years' Papers:
- The mock tests provided by EduRev are designed to closely resemble the previous years' papers of the UPSC Chemistry optional.
- The questions are carefully curated to reflect the types of questions that have been asked in the past.
- This helps candidates familiarize themselves with the pattern of the paper and allows them to practice solving similar questions.

3. Comprehensive Coverage:
- The mock tests cover the entire Chemistry optional syllabus prescribed by UPSC.
- They include questions from various topics such as Inorganic Chemistry, Organic Chemistry, Physical Chemistry, and Analytical Chemistry.
- This comprehensive coverage ensures that candidates are well-prepared for all the different areas of the subject.

4. Evaluation and Feedback:
- After completing the mock tests, candidates receive detailed evaluations and feedback on their performance.
- This feedback helps them identify their strengths and weaknesses in different topics and concepts.
- Candidates can use this feedback to focus on areas that require improvement and further enhance their preparation.

5. Time Management:
- The mock tests also provide candidates with an opportunity to practice time management.
- They are designed to be completed within a specific time limit, similar to the actual UPSC examination.
- This helps candidates improve their speed and accuracy in answering questions within the given time frame.

Conclusion:
Mock tests that simulate the previous years' papers of UPSC Chemistry optional are available on platforms like EduRev. These tests provide a comprehensive coverage of the syllabus, simulate the pattern and difficulty level of the actual exam, and help candidates evaluate their performance and improve their time management skills.