Q.What are antacids? Give example.

Magnesium hydroxide is an antacid — option (A).

Antacids are mild bases that neutralise excess hydrochloric acid in the stomach, relieving acidity. Magnesium hydroxide, Mg(OH)2 (milk of magnesia), reacts with HCl to form MgCl2 and water, raising the stomach pH.

• Phenacetin → an analgesic/antipyretic. …

Milk of Magnesia ($Mg(OH)_2$ suspension) is a mild base that neutralises excess stomach HCl; drugs used for this purpose are classed as antacids.

Milk of Magnesia is the common name for an aqueous suspension of magnesium hydroxide. It is a weak, insoluble base, so it reacts slowly and safely with the excess hydrochloric acid secreted in the stomach: $Mg(OH)_2 + 2HCl \rightarrow MgCl_2 + 2H_2O$, relieving acidity/heartburn. This is exactly the defining action of an antacid (a drug that neutralises excess stomach acid), unlike a t …

Antacids are basic substances taken to counteract the excess gastric HCl responsible for acidity/heartburn.

Antacids are chemical substances (generally weak bases) that neutralise the excess hydrochloric acid secreted by the gastric glands of the stomach, providing relief from acidity, indigestion, and heartburn. They act simply by an acid-base neutralisation reaction, e.g.:

$Mg(OH)_2 + 2HCl \rightarrow MgCl_2 + 2H_2O$

…

Over-acidity is treated by antacids (mild bases that neutralise HCl).

The stomach secretes hydrochloric acid for digestion. Its overproduction causes acidity/hyperacidity. Antacids (e.g. metal hydroxides like Mg(OH)2, Al(OH)3, or NaHCO3, and drugs like ranitidine/omeprazole) are basic and neutralise or reduce the excess a …