can I receive pending messages of whatsapp after I reactivate my account on new phone? Can I receive pending messages from WhatsApp that was in my dead phone
 but still pending coz of the dead phone when I reactivate my account on the new phone??
I am mentioning again pending (undelivered) messages??
can I receive back after re-installing in the new phone???
As long as you register your phone number on a new device within 45 days, you will receive all pending messages.

After 45 days, registering WhatsApp on a new device will be as if you never had WhatsApp before, no groups, no pending messages, no profile picture. 
(But you will still be able to retrieve your old messages from Google drive (not the pending ones though))