Home
Class 11
CHEMISTRY
Assertion: If BOD level of water in a re...

Assertion: If `BOD` level of water in a reservoir is less than 5 ppm it is highly pollution.
Reason: High biological oxygen demand means low activity of bacteria in water.

A

Both A and R are correct and R is the correct explanation of A.

B

Both A and R are correct but R is not the correct explanation of A.

C

Both A and R are not correct.

D

A is not correct but R is correct.

Text Solution

Verified by Experts

The correct Answer is:
C
Correct Assertion. If BOD level is less than five, water is almost pure.
Correct Reason. High biological demand means low activity of bacteria in water.
Promotional Banner

Similar Questions

Explore conceptually related problems

Assertion : Ice cube floats on water. Reason : Density of ice is less than that of water.

BOD value less than 5 ppm indicates a water sample to be

"Determination of Biological oxygen demand (BOD) can help in suggesting the quality of a water body. " Explain

Assertion: A dam for water reservoir is built thicker at bottom than at the loop. Reason : Pressure of water is very large at the bottom.

Assertion : BOD of river polluted by sewage is more than 20 ppm. Reason: Polluted river contains excess of organic matter.

Assertion: The viscosity of water is less than blood. Reason : The viscosity of liquids decreases with increases in temperature.

Assertion : In desert area, days get hot fastly and the nights get cold fastly . Reason : The specific heat capacity for air and land is less than that of water.

Assertion: Decrease in the vapour pressure of water by adding 1 mol of sucrose to one kg of water is higher to that produced by adding 1 mol of urea to the same quantity of water at the same temperature . Reason : Molecular mass of sugar is less than that of urea .

Assertion : Carotenoids play a protective role for the chloroplasts during photolysis of water. Reason : Carotenoids pick the nascent oxygen by means of their double bonds and convert the same into molecular state.

Assertion : The amount of BOD in the water is a measure of the amount of organic material in the water . Reason : Clear water has BOD less than 5 ppm whereas highly polluted water can have BOD value of 17 ppm or more .