Compatibility summary
Your South Korea plug may fit in Republic of the Congo outlets, as both use at least one common plug type.
Plug comparison
South Korea plug types: C F
Republic of the Congo plug types: C E
Both countries share at least one plug type (C F and C E), so some plugs may work without an adapter. Check your appliance.
Voltage comparison
South Korea: 220V, 60Hz
Republic of the Congo: 230V, 50Hz
Voltage difference is within a range many devices tolerate; check your appliance label.