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
Understanding X-ray Examination of the Alimentary Canal
Examining the internal organs like the alimentary canal using standard X-rays can be challenging. X-rays pass through soft tissues such as the esophagus, stomach, and intestines relatively easily, making it difficult to see their structure, shape, and any abnormalities clearly. To overcome this limitation, doctors use a special technique called contrast radiography.
What is a Contrast Medium for Alimentary Canal X-rays?
A contrast medium is a substance that is introduced into the body to improve the visibility of internal structures on X-ray images. For the alimentary canal, the contrast medium is usually ingested or administered rectally. The ideal contrast medium for this purpose should have several key properties:
- It must be safe to ingest and pass through the digestive system without being absorbed into the bloodstream in significant amounts.
- It must be non-toxic.
- It must be opaque to X-rays, meaning it effectively blocks or absorbs X-rays, creating a clear outline or filling of the structures it occupies.
- It should ideally coat the lining of the organs to highlight their inner surface.
Analyzing the Metal Salt Options for Alimentary Canal Examination
Let's look at the given metal salt options and see which one fits the criteria for a safe and effective contrast medium for an X-ray examination of the abdomen (alimentary canal).
1. Barium Sulphate (\(\text{BaSO}_4\))
Barium is a heavy metal with a high atomic number, making it very effective at absorbing X-rays. Barium sulphate is a specific compound of barium. Crucially, barium sulphate is highly insoluble in water and biological fluids. This insolubility is key because it prevents the absorption of toxic barium ions into the bloodstream from the gut. When administered as a suspension (often called a 'barium meal' or 'barium swallow'), it coats the lining of the esophagus, stomach, and intestines, making them clearly visible on X-ray images.
2. Barium Chloride (\(\text{BaCl}_2\))
Barium chloride is a soluble salt of barium. If ingested, it would dissociate into barium ions (\(\text{Ba}^{2+}\)) and chloride ions (\(\text{Cl}^-\)) in the digestive tract. Barium ions are toxic if absorbed into the body. Because barium chloride is soluble, the barium ions could be absorbed, leading to poisoning. Therefore, barium chloride is not safe for internal use as a contrast medium.
3. Strontium Sulphate (\(\text{SrSO}_4\))
Strontium sulphate, like barium sulphate, is relatively insoluble. Strontium is also a heavy element and would provide some contrast. However, strontium is chemically similar to calcium and can be absorbed and deposited in bones. While strontium sulphate is less soluble than strontium chloride, it is not the standard or preferred contrast agent for the alimentary canal. Barium sulphate is more widely used due to its optimal opacity and inertness when insoluble.
4. Magnesium Chloride (\(\text{MgCl}_2\))
Magnesium chloride is a soluble salt. Magnesium ions (\(\text{Mg}^{2+}\)) are absorbed to some extent, and while magnesium is an essential element, large amounts can have a strong laxative effect and other physiological impacts. Magnesium also has a much lower atomic number than barium, making it less effective at blocking X-rays and providing adequate contrast for the alimentary canal structures compared to barium sulphate.
Conclusion: The Safe and Effective Contrast Agent
Based on the properties required for a safe and effective X-ray contrast medium for the alimentary canal – namely, high X-ray opacity and minimal absorption/toxicity – barium sulphate is the correct choice. Its insolubility ensures that the toxic barium ions are not significantly absorbed by the body as the compound passes through the digestive system.
| Salt | Chemical Formula | Solubility | Toxicity Risk (if absorbed) | X-ray Opacity | Suitability for Alimentary Canal X-ray |
|---|---|---|---|---|---|
| Barium Sulphate | \(\text{BaSO}_4\) | Very Low (Insoluble) | Low (due to insolubility) | High | Highly Suitable (Standard) |
| Barium Chloride | \(\text{BaCl}_2\) | High (Soluble) | High (Barium ions are toxic) | High | Not Suitable |
| Strontium Sulphate | \(\text{SrSO}_4\) | Low (Insoluble) | Lower than soluble Sr, but Ba preferred | Moderate (Lower than Ba) | Not Standard/Preferred |
| Magnesium Chloride | \(\text{MgCl}_2\) | High (Soluble) | Low-Moderate (Laxative, physiological effects) | Low | Not Suitable |
Therefore, barium sulphate is the metal salt administered in a patient's meal for an X-ray examination of the alimentary canal.
Revision Table: Key Concepts for Alimentary Canal X-ray
Let's quickly review the important points related to using metal salts for alimentary canal X-rays:
- Purpose: Visualize soft tissues like esophagus, stomach, intestines on X-rays.
- Challenge: Soft tissues don't block X-rays well.
- Solution: Use a contrast medium.
- Ideal Contrast Medium Properties: Non-toxic, insoluble (for oral use), high X-ray opacity.
- Standard Agent: Barium Sulphate (\(\text{BaSO}_4\)).
- Why \(\text{BaSO}_4\)?: Highly insoluble, prevents toxic barium absorption, high atomic number gives good X-ray contrast.
- Why not others?: Soluble barium salts (\(\text{BaCl}_2\)) are toxic. Soluble salts like \(\text{MgCl}_2\) have less opacity and potential side effects. Strontium sulphate is less common/effective than barium sulphate.
Additional Information: Barium Meal Procedure
The procedure involving barium sulphate is commonly known as a barium meal or barium swallow (for the upper part of the alimentary canal like esophagus and stomach). The patient drinks a suspension of barium sulphate. X-ray images are taken as the barium passes through the digestive tract. This allows doctors to examine the shape, size, and movement of these organs, as well as detect ulcers, strictures, tumors, or other abnormalities. After the procedure, the barium is naturally eliminated from the body in the stool.
Similar Questions
Which one of the following is used in soda-acid fire extinguishers?
Which one of the following gases is released mostly from landfills in urban areas?
After a hot sunny day, people sprinkle water on the roof-top because:
Methyl Isocyanate gas, which was involved in the disaster in Bhopal in December 1984, was used in the Union Carbide factory for the production of:
‘German silver’ is used to make decorative articles, coinage metal, ornaments, etc. The name is given because:
- Why do plastics not degrade easily ?
- The surface of the concrete structure of a new construction is covered with straw/gunny bags by wetting. This is done to :
Bright light is found to emit from photographer’s flashgun. This brightness is due to the presence of which one of the following noble gases?
Which one among the following substances is a compound?
Which one of the following statements regarding acids is not correct?
Important Questions from Chemistry in Everyday Life
Which of the following is a greenhouse gas?
I. Methane
II. Nitrous oxide
Among the following, the conducting form of carbon is
Which of the following is NOT a Fossil Fuel?
Which one of the following is used in soda-acid fire extinguishers?
The separation of two immiscible liquids can be done based on the difference in their_______.
