answer: c. the experiment shows that the red substance experienced a chemical change.
explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.
chemical changes are accompanied by following changes:
a) precipitate formation
b) energy is released or absorbed
c) formation of bubbles
d) change in color
as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.
atomic number of carbon is 6
electronic configuration of carbon is 1s²2s²2p²
orbital diagram of carbon is as shown here in the image.