rate of gst under reverse charge

Composition Scheme Dealer need to pay tax as under:
a) 2% - Manufacturer
b) 5% - Restaurant Services
c) 1% - Any other.

The person to whom the supply is made shall not be made to pay GST under RCM as the RCM provision shall apply only if the goods are notified goods or the supplier is an unregistered person. Composition Scheme Dealer should not be treated as URD

if i (opted composition scheme) purchase goods from unregistered dealer then at what rate i have to pay under RCM