Final answer:
El Salvador is the smallest and most densely populated country in Central America with no Caribbean coastline, with San Salvador as its capital.
Step-by-step explanation:
The smallest and most densely populated country in Central America that does not have a coastline on the Caribbean is El Salvador. It is known as the land of volcanoes and is bordered by the northern Pacific Ocean, Guatemala to the northwest, and Honduras to the southeast. The capital city is San Salvador and Spanish is the official language. Despite its size, El Salvador's population is estimated to be over six million people as of 2017, predominantly Mestizos who constitute 86.3% of the population.