What is the longest single penalty ice hockey?

Answer 1

The longest singly penalty I'm aware of in the NHL is 9 minutes on December 5, 2009, against the Philadelphia Flyers vs. Washington Capitals.

The nine minute power play at Philadelphia began 14:33 of period #1 and carried over into the second. Flyer's Dan Carcillo and Matt Bradley got into a shoving match at center ice, and Philadelphia's Carcillo landed a big punch as Bradley was dropping his gloves. Bradley fell to the ice and left the game. Carcillo received 19 minutes of penalties and a game misconduct, resulting in the power play.