Q. Arrange the following options in ascending order of their BOD value. Sample of highly polluted pond water. Sample from unpolluted pond water. Distilled water.
A) III $\rightarrow$ I $\rightarrow$ II
B) II $\rightarrow$ III $\rightarrow$ I
C) III $\rightarrow$ II $\rightarrow$ I
D) I $\rightarrow$ III $\rightarrow$ II
Explanation
Biochemical oxygen demand is the oxygen in milligrams required for five days in one liter of water at $20^{o}C\$for the microorganisms to metabolise organic waste. BOD increases with increase of pollution.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.