Is rcm to be paid on goods and services purchased from un registered dealer. Also will it be applicable on rent. If not please provide notification.

Reply—Provision of section 9(4) of CGST Act, i.e. reverse charge mechanism in case of inward supplies of goods and services made from unregistered person was operative upto 12.10.2017. It is not applicable now. 

As per notification No. 38/2017 CT (Rate) dated 13-10-2017, all supplies from unregistered person are exempted without any threshold limit.  The subsequent Notifications no. 22/2018-Central Tax (Rate) dated 06-08-2018 has extended the exemption from tax liable under the reverse charge basis under section 9(4) till 30-09 2019. After that this notification has been rescinded by CBIC.