I wish to obtain clarity on the usage of preposition on and in.
Is it acceptable to start one's sentence with a preposition.
As regards your second question, Yes, you can start a sentece with a preosition. Flowing are few examples:
In which year did Marconi invent wireless and telegraphy?
On which day we celebrate the youth day?
According to Jane, the banana is inside the box. (according to is a prepositional phrase)