UPSC Civil Services (Mains), Chemistry optional · 2025 · Paper I
Q3(e). Why crystals have more defects at higher temperature
Question
Explain why crystalline solids are generally more defective as a result of increasing temperature.
Answer in brief
Making a defect costs enthalpy but adds entropy; the entropy term is multiplied by T, so the equilibrium number of defects rises with temperature.
Part of VKC Basic
Read the key points and the full model answer with VKC Basic
VKC Basic (₹999 for 6 months) opens every solved answer, the notes, the handbook and the daily answer archive. Every Mains test series includes it.
The full model answer
As written for the answer booklet: the diagram carries the working, the lines stay short. Read here only; it is not offered as a download.
The handwritten model answer pages open with the VKC plan.
Coverscrystal defectsconfigurational entropyvacancy concentrationSchottky defectGibbs energy minimum
All parts of Question 3
- 3(a) Collisions of O₂ with the wall10 marks
- 3(b) Droplets made from one mole of water15 marks
- 3(c) Phase diagram of butane and two compressions10 marks
- 3(d) Water condensed while ice melts and warms10 marks
- 3(e) Why crystals have more defects at higher temperature5 marks