Selenous acid is diprotic it can react with sodium hydroxide in steps write equations (in molecular form) for the two steps of the reaction

The chemical formula for the selenous acid is H2SeO3. Its reaction with sodium hydroxide, which has a chemical formula of NaOH, will be a neutralization reaction forming a salt and water. This is depicted below.

             H2SeO3 + NaOH à Na2SeO3 + H2O

If we are to balance the chemical reaction then, we will have a final answer of,

        H2SeO3 + 2NaOH à Na2SeO3 + 2H2O

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.

e

atomic number of carbon is 6

electronic configuration of carbon is 1s²2s²2p²

orbital diagram of c is as shown here in the image.