Yes, there are several journals and publications that provide practice questions for the Chemistry optional subject:

1. EduRev:
- EduRev is a highly recommended platform that offers practice questions, study materials, and mock tests for various competitive exams, including the UPSC exams.
- It provides a wide range of practice questions specifically for the Chemistry optional subject, covering different topics and concepts.
- The questions are designed by subject matter experts and previous exam toppers, ensuring their relevance and quality.
- EduRev also offers detailed solutions and explanations for each question, helping students understand the concepts thoroughly.

2. Chemistry World:
- Chemistry World is a reputable publication that covers the latest advancements, research, and developments in the field of chemistry.
- While it primarily focuses on scientific articles, it may also feature practice questions or quizzes related to different aspects of chemistry.
- These questions can be beneficial for those preparing for the Chemistry optional subject as they provide an opportunity to test and enhance their knowledge in a practical manner.

3. Journal of Chemical Education:
- The Journal of Chemical Education is a peer-reviewed academic journal that publishes research papers, teaching materials, and resources related to chemistry education.
- Although it does not specifically provide practice questions for the Chemistry optional subject, it offers a wealth of information and educational content that can be useful for students preparing for UPSC exams.
- The journal covers a wide range of topics and concepts, which can help students deepen their understanding of chemistry and strengthen their problem-solving skills.

4. Previous Years' Question Papers:
- Another valuable resource for practice questions is previous years' question papers of the UPSC exams.
- These papers can be obtained from various sources, including official UPSC websites, educational forums, and coaching institutes.
- By solving these question papers, students can familiarize themselves with the exam pattern, understand the type of questions asked, and assess their preparation level.
- Additionally, analyzing the solutions and marking schemes of these papers can provide insights into the expected answers and help in improving time management skills.

Overall, utilizing these resources, such as EduRev, Chemistry World, Journal of Chemical Education, and previous years' question papers, can greatly enhance the preparation for the Chemistry optional subject in UPSC exams.