You can get past few years class 12 MBOSE question papers from the official site of Meghalaya Board of School Education. Follow the steps below to download the question papers:
- Open the official site of MBOSE
- Scroll down at the bottom of the home page
- At the bottom right side you will find a section named "Question papers"
- Click on the particular year under "Class XII"
- A zip file will start downloading which contains question papers of all the subjects of Class 12
- After download extract the zip file to get the pdfs
- Now open the chemistry pdfs to see the Class 12 chemistry paper of the respective year
Hope it helps!
Best of luck!