The number of currently incomming requests can be found using netstat: netstat -anp | grep :80
Just read the number where the destination address is your servers ip with the port 80.
To find the maximum number of requests apache can handle just look in the httpd.conf file for the MaxClients directive. There should be some other information regarding child processes and how many clients per process each can hold.
@username456453 the suggestion of blud is correct, on a server platform you can check the incoming connections through netstat command, it's quite different from the desktop platform that you are using in your assertion, and even if opening a page (into a server/desktop environment) loads multiple requests, this will be detected by the netstat command.