CODEC AD1836A  ADC verification

CODEC AD1836A AD converter working in differential input mode: ( Gain=1)

We have:

ADC2 Left Input 1=2.25V +small AC signal

ADC2 Left input 2=2.25V

Differential mode setting and gain=1.

The Data sheet says

Full-Scale Input Voltage (Differential) 2.18V ( RMS), 24 bit ADC

My question is :

(1)  If differential input voltage= -0.1V, what is the ADC2 digital output? Is ADC2 unipolar or bipolar?

(2) If differential input voltage=0.1V, what is the ADC2 digital output?

(3) if the differential input voltage is constant DC voltage, then will the ADC 2 output  be zero?

We have experience with other ADC, such as AD7714, but not familiar with ADC for CODEC.

we would like understand, verify and test how CODEC ADC works.