Assuming that this question is about adapters for traveling to another country (not USA) then 230V is the equivalent of 220V. Just purchase a suitable adapter.
Yes, you can use a 230V 50Hz AV receiver in a 220V 60Hz electrical system. The small difference in voltage and frequency should not cause any significant issues or damage to the AV receiver. However, it's always a good idea to check the manufacturer's recommendations or consult with a professional to ensure compatibility.
No! Normally not, the recistance in the windings is to hig on 60Hz and the pump motor has not power enough to work propelly. This happened to myself when I connected my Whirpool AWE 7519 to 230V 60Hz. Europian model for 50Hz.
you can't
230V/50Hz
Yes, no problem.
220v 50Hz
Most likely, yes. Most devices has been manufactured with an idea that they will be used in areas where the supply power frequency is 50 or 60Hz.
nothing
There should be no problem at all.
220V , 50Hz
It is generally safe to use a 230V 50Hz appliance in a 220V 60Hz outlet, as the difference in frequency should not significantly affect the operation. Make sure to check if the appliance is dual voltage compatible and be cautious of potential power surges or overheating. However, it is always recommended to use a voltage converter or transformer for long-term use to prevent any damage to the appliance.