What is gst rates on chats and snacks business?

5% ..

5% will be the rate

if not opted for composition, what will be the GST rates

Not opted then also rate will be 5% with out ITC

So, ITC cannot be claimed at all and mandatory to opt composition

what is the difference in opting composition and not opting it. I mean the GST cash flow will be the same in both cases. Am I right?

being a regular dealer you can collect tax from customers by mentioning in the imvoice..... being a composition dealer you are not allowed to do that so you have to bear the cost( which you will recover from ur customer by increasing price of the product) so ultimately there is no difference.... in both cases the customer have to suffer.......