Hello,
I understood the section that you want to get implemented. I have a suggestion for you that you better ask for a URL like ncertsolution/class12/11_1/Q1 instead of ncertsolution/class12/11.1Q1.htm. The advantage of doing so is that it is SEO friendly and also doing so will require just only one page rather than multiple pages corresponding to each solution.
Except that I have one query for you, I just want to know how you are storing solution? Are you storing it in database then it is great, but if you are planning to create page for all the solution, then it wont be a good idea.
I wish to give one more suggestion regarding the container. You are wishing to place an iframe, I think div would be a better alternative to display solution.
Well, I am interested in this project. In case you want to contact me please send me a mail at my contact email.
Thanks and Regards