Question

Which of the following are used as an antacid to reduce acidity in stomach?

• A. Sodium carbonate and magnesium hydroxide
• B. Magnesium hydroxide and sodium hydroxide
• C. Sodium bicarbonate and calcium hydroxide
• D. Sodium bicarbonate and magnesium hydroxide

Answer 1

Answer: (D)

Sodium bicarbonate and magnesium hydroxide

Acidity of stomach has to be neutralized by a base, without affecting or damaging the cells of the body.

$Ca(OH{)}_2$ is highly caustic while $Mg(OH{)}_2$ is not, because it has very low solubility in water. Similarly, $NaHC{O}_3$ is a weak base.

Thus, $NaHC{O}_3$ and $Mg(OH{)}_2$ are used as an antacid (against gastric acids like HCl).

$NaHC{O}_3+HCl\to NaCl+H_{2}O+C{O}_2\uparrow$

$Mg(OH{)}_2+2HCl\to MgC{l}_2+2H_{2}O$