Which among the following elements is not present in salvarsan?

Among the following,which is an antacid?

Which one of the following chemicals is responsible for the production of $HCl$ in the stomach leading to irritation and pain?

Synthetic detergents have an advantage over usual soaps regarding cleansing power. However,the long-term use of synthetic detergents creates environmental pollution. How can the pollution caused by synthetic detergents be minimized? Classify the detergents according to their chemical nature.

Artificial sweetener used in soft drinks is

$A$ food additive that acts as an antioxidant is