Hi

Sorry to tell you but you have not mention the name of the exam for which you want the list of difficult topics subject wise

But without knowing the name of the exam, we can not help you

So, do let us know the name of the exam so that we can help you with relevant and detailed information

In case if you are asking about jee, then some of the most difficult chapters are provided below subject wise ,-

PHYSICS:-

• Rotational mechanics
  
• Electrostatics
  
• Quantum Mechanics
  
• Thermodynamics
  
• Mechanics

CHEMISTRY

• Ionic Equilibrium
  
• Electrochemistry
• GOC
  
• Solutions
  
• Chemical Thermodynamics
  

MATHS

• Complex Numbers
• Permutation and combinations
  
• Probability
  
• Definite Integral
  
• Indefinite Integral
  
• Application of Derivatives
  
• Differential equation

Thankyou