[L] contain weak alkalis such as magnesium hydroxide and aluminium hydroxide to neutralize the excess acid in the stomach in order to relief stomachache.

The statement "[L] contains weak alkalis such as magnesium hydroxide and aluminium hydroxide to neutralize the excess acid in the stomach in order to relieve stomachache" refers to the use of antacids.

Here's a step-by-step explanation:

1. The stomach naturally produces hydrochloric acid to help break down food. However, too much stomach acid can cause discomfort and lead to conditions like acid reflux or ulcers.

2. Antacids, such as those containing magnesium hydroxide and aluminium hydroxide, are often used to treat these conditions. These substances are weak bases (alkalis) that can neutralize the excess acid in the stomach.

3. When an antacid is consumed, it reacts with the stomach acid. This reaction produces salt and water, which are harmless and can be easily excreted from the body.

4. By neutralizing the stomach acid, antacids can relieve symptoms such as heartburn and indigestion, which are often described as a 'stomachache'.

5. Therefore, the statement is explaining how antacids work to relieve discomfort caused by excess stomach acid.