Too much baking soda will give the cake a bitter taste, and may cause the cake to rise too high and collapse. This will Result in a ruined or unappetizing cake.
Mostly it will just taste salty, though the baking soda can interfere with the other chemical changes going on in the cake, resulting in a pretty unappetizing confection.
The taste will be bad soapy kinda.
try soda water instead of baking soda in the recipe of cake.
for amount google out 'tanu tried n tasted' chocolate cake.
Too much baking soda may cause the cake to rise too much. After cooling, the cake will then fall. Additionally, the cake may have an "off", salty or metallic flavor.
Too much of baking soda can cause the batter to be bitter in taste taste 7 such batter may suddenly rise rapidly and then collapse. The Cake will eventually suffer a fallen center,coarse & fragile crumb.