ANSWER
KCN is an electrolyte
EXPLANATION:
Firstly, we need to define electrolyte
An electrolyte is a substance that conducts electricity when dissolved in water. An electrolyte is a medium containing ions that are electrically conducting through the moving ions.
A good electrolyte includes soluble salts, acids, bases that dissolved in a polar solvent
Note that, all group one elements are soluble and potassium is a group one element
When KCN is dissolved in water, it dissociates into the following ions
[tex]\text{KCN }\rightarrow K^++CN^-[/tex]Hence, KCN is a good and strong electrolyte because of its strongly basic nature, and also, it is soluble in water.