Can a Btech final year students appear for TNPSC exams??? What are the basic requirements to apply???

Yes Btech final year students can appear for Tamil Nadu Public Service Commission exams. Basically the eligibility conditions are as following:

Eligibility:
The applicant should have completed bachelor’s degree in any discipline from a recognized university. Final year students can also apply.

Age limit:
Candidate’s age should be between 21 years and 30 years.
Relaxation in age,
Upto 33 years for OBC,
Upto 35 years for Sc / ST

Syllabus of this exam
General awareness(100 marks) and General English(100 marks).
General Tamil(100 marks) and General English(100 marks).

TNPSC recruits candidates for following posts:

Assistant Central Secretariat Service
Assistant Central Vigilance Commission
Inspector (Central Excise)
Inspector (Preventive Officer)
Assistant Ministry of Railway
Statistical Investigator Gr.II
Assistant Ministry of External Affairs
Assistant (Cypher) Ministry of External Affairs
Assistant Ministry of Defence
and many more