one gst no for two different business allowed or not

Yes you can ....... but must not have registered as composit dealer

ok sir thank you

Please note that ITC is not allowed if you pay taxes at 5% for restaurant business. Whereas your other business of construction you might be availing credit.

There is always risk in such scenario's with respect ITC.

Better go with separate business veritical registration under GST and maintain two books of accounts.