A patient’s abdomen (alimentary canal) can be examined by X-ray after

A patient’s abdomen (alimentary canal) can be examined by X-ray after administering which one of the following metal salts in the patient’s meal ?

Barium sulphate
Barium chloride
Strontium sulphate
Magnesium chloride
This question was previously asked in
UPSC CDS-2 – 2022
Barium sulphate is administered to patients for X-ray examination of the alimentary canal. This procedure is commonly known as a barium swallow, barium meal, or barium enema depending on the part being examined.
– Barium sulphate (BaSO4) is a contrast agent used in radiology.
– It is opaque to X-rays, allowing the structure of the digestive tract to be visualized.
– It is used because it is insoluble in water and is not absorbed by the body, making it relatively safe for ingestion or rectal administration despite barium being toxic.
Other barium salts, like barium chloride, are soluble and toxic, and thus cannot be used for this purpose. Barium sulphate is chemically inert and passes through the digestive system without being absorbed.