Question

which Constitution of Nepal declared the country a federal
nation​

Answer 1

Answer: On December 28, 2007, the Interim Parliament passed a bill and declared Nepal to become a Federal Democratic Republic. The first meeting of the Constituent Assembly officially implemented that declaration on May 28, 2008. Nepal is a multi-cultural, multi-linguistic and multi religious country.

i hope this helps! <:D

Answer 2

Nepaali is the national language of nepal
Hope you understand