rt.exec("cmd.exe /c start cd \"C:/Program Files (x86)/Google/Chrome/Application&chrome.exe\"");
Not tested but this shall work, I just put the complete path in double quotes so that because of spaces it's not considered to be the next argument.
If that doesn't work, I suggest trying Apache Commons Exec library, because I always use that.
Here is some sample code from one of my applications :
CommandLine cmdLine = new CommandLine("cmd.exe");
cmdLine.addArgument("/c");
cmdLine.addArgument(".\\phantomjs\\nk\\batchbin\\casperjs.bat");
cmdLine.addArgument(".\\phantomjs\\nk\\batchbin\\dd.js");
cmdLine.addArgument(url);
cmdLine.addArgument(">" + rand);
DefaultExecutor executor = new DefaultExecutor();
int exitValue = executor.execute(cmdLine);
Using something like above the complete path to chrome.exe should be added as a new argument, and then the library will take care of escaping.