<u>Answer:</u> The correct answer is Option d.
<u>Explanation:</u>
According to Lewis acid-base concept:
The substance which is donating electron pair is considered as Lewis base and the substance which is accepting electron pair is considered as Lewis acid.
For the given chemical reaction:

is accepting electron pair and is getting converted to
. Thus, it is considered as Lewis acid.
present in CuO is a Lewis base because it is donating electron pair.
Thus, the correct answer is Option d.
The gastric chief cells of the stomach secrete enzymes for protein breakdown (inactive pepsinogen, and in infancy rennin). Hydrochloric acid activates pepsinogen into the enzyme pepsin, which then helps digestion by breaking the bonds linking amino acids, a process known as proteolysis.
O,P,Ge ranked from atomic radius
The number of protons, neutrons, and electrons in an atom can be determined from a set of simple rules. The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons.