recieve ACK after sending address in I2C in EFR32FG14
Every transaction requires you send nine clock pulses from the master, the month byte is for the ACK bit.
For the slave address transaction the data line is left high from the master so the slave can acknowledge the address if recognized.
If you are using the I2C hardware it will automatically send nine clock pulses. If being implemented in software you will need to send all nine clocks by setting the clock high and then low.