Notice how the K and Ag are both being swapped around.
Single Replacement:
A+BX → B+AX
Double Replacement:
AX+BY → BX + AY
And a water molecule, this is called a dehydration synthesis. when 2 molecule combine, a water molecule leave.
Answer:
An acid is a substance that donates protons (in the Brønsted-Lowry definition) or accepts a pair of valence electrons to form a bond (in the Lewis definition). A base is a substance that can accept protons or donate a pair of valence electrons to form a bond. Bases can be thought of as the chemical opposite of acids.