UPSC Prelims 2024 Q36: Science & Technology – Chemistry
In which of the following are hydrogels used?
1. Controlled drug delivery in patients
2. Mobile air - conditioning systems
3. Preparation of industrial lubricants
Select the correct answer using the code given below:
- (a) 1 only
- (b) 1 and 2 only
- (c) 2 and 3 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
Hydrogels — water-holding polymer networks
A hydrogel is a 3D network of polymer chains that can hold large amounts of water without dissolving.
| Use | Applies? | How hydrogels are used |
|---|---|---|
| 1. Controlled drug delivery | Yes | They swell and release a drug slowly; used in wound dressings and contact lenses |
| 2. Mobile air-conditioning | Yes | Hydrogels absorb moisture and cool by evaporation; researched for passive cooling of devices and vehicles |
| 3. Industrial lubricants | Yes | Their water-rich surfaces give very low friction (hydration lubrication) |
Other hydrogel uses:
| Field | Example |
|---|---|
| Agriculture | Water-retaining granules in dry soils |
| Hygiene | Super-absorbent polymers in diapers |
| Medicine | Tissue engineering scaffolds, soft contact lenses |
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. Drug delivery is the best-known use, but hydrogels are also used for cooling and lubrication.
- (b) Incorrect. It leaves out industrial lubrication, where hydrogels give very low friction.
- (c) Incorrect. It leaves out drug delivery, the most established medical use.
- (d) CORRECT. Hydrogels are used for drug delivery, evaporative cooling and lubrication.
Key point
Hydrogels hold large amounts of water: used in drug delivery, evaporative cooling, lubricants, farming and diapers.
Remember
Hydrogels are used in drug delivery, cooling systems and lubricants.
Common mistakes
- Thinking hydrogels are only medical; they are also used in farming, cooling and engineering.
- Confusing hydrogels with aerogels, which are ultra-light solids full of air.
- Not linking moisture absorption to evaporative cooling, which is how hydrogels help air-conditioning.
Exam tip
Think of what water can do: carry drugs, cool by evaporating, and reduce friction. Hydrogels do all three.
Sources
- NCERT Class XII — Chemistry (Polymers)
- Nature Reviews Materials — Hydrogels for biomedical and engineering applications