Hey Histish,

CA is professional courses having 3 level ,generally it is 4 years course but only if you pass all 3l level in first attempt 

Three levels of exam are:

• CA Foundation 
  
• CA IPCC also known as Intermediate Course 
• CA Final 

B. Com is 3 years undergraduate degree. Now it is  6 semesters course each year has 2 semesters which is basically 6 months gap for every semester 

Now,  talking about syllabus both CA IPCC and B. Com Honours has almost same syallbus but CA demand your full attention in each and every concepts compare to b.com (H) . If you want to go for correspondence you can opt for b. Comp honours  but only if you can manage both the courses and I would suggest you to pursue b. Com for the option in future only. 

My best wishes to you!!