Do not pour chemical drain unblocker through the disposer as a troubleshooting step. Follow the appliance's cleaning restrictions and have the location of a blockage assessed without adding hazardous liquid to the system.
What the observation tells you
A blocked drain can retain the chemical where it is difficult to see. The next attempt to open a connection could expose someone to it, and compatibility with the disposer and its seals cannot be assumed. Mixing products increases the uncertainty.
A useful next step
Keep the motor off and stop adding water if the sink is backing up. If a product has already been used, disclose its name and timing before anyone works on the appliance.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.