where is the pair of scissors
where is mother and father
together but reflected upon as a singular
The word "pair" is singular, that's why. If you're asking "Where are the scissors?" or "Where are the parents?" it's plural. Parents = mom and dad.
OK I finally found some reference.
When a compound subject follows the verb and the first element is singular, the verb may be either singular or plural (Merriam-Webster Guide to English Usage)
"is" is accepted now