Can someone tell me if this kind of RS232-USB cable can be used to connect a usb wifi dongle to the serial port of a PC? If not, how can this be done?
Can someone tell me if this kind of RS232-USB cable can be used to connect a usb wifi dongle to the serial port of a PC?
No.
If not, how can this be done?
It cannot. Although you might be able to get some kind of physical connection you won't be able to use the WiFi network the dongle should provide.
Anyway, tell us what you want to accomplish and not just how you plan to do that. Do you plan to bring WiFi to an ancient PC with just an RS-232 interface?
Yes, exactly. Can this be done? i.e. turn the RS-232 serial port into a USB port.
Not possible.
USB protocols are totally incompatible with RS232 serial ports.
Why do you want to do this?
Do you have a PC with no USB ports?