UV Visible Spectroscopy – Pharmacognosy & Phytochemistry
1.What is the wave length range for UV spectrum of light?
A. 400 nm to 700 nm
B. 700 nm to 1 mm
C. 0.01 nm to 10 nm
D.10 nm to 400 nm
Answer:- D
Explaination: Ultra violet (UV) is an electromagneti cradiation with a wave length from 10 nm to 400 nm,shorter than that of visible light but longer than X-rays (the visible region fall between 380-750 nm and X-rays region fall between 0.01to 10nm).
2.Which of the following comparison is correct for solvent shift on the transition of acetone?
Answer:- C
Explaination: H-bonding with ground state in results in increase in energy gap & decrease in wave length. And as polar solvents show strong H-bonding. So,the correct option is C
3.What is the correct order of λmax for transition?
Answer:- B
Explaination: According to molecular orbital energy diagram for R-OH, R-NH , R-SH (shown below), energy level will decrease respectively so λmax will increase.
