There are two extensions:
Open with external application by Lorenz Cuno Klopfenstein
Opens any link of a webpage with a custom external application.
"Open with external application" (in dire need of a better name) is an extension for the Google Chrome web browser. It allows the user to select any executable and use links of the web pages s/he is browsing as a command line parameter when launching such executable.
The user might, for instance, decide to open a target link in Firefox, Opera, Safari or any other application capable of handling an URL parameter.
Get it here https://chrome.google.com/webstore/detail/open-with-external-applic/hccmhjmmfdfncbfpogafcbpaebclgjcp
If you prefer Firefox there is Open With Firefox by bnk
Get it here https://chrome.google.com/webstore/detail/open-with-firefox/jmjejjdalfogiopknpabihjhplfkjjjk