Question

Which of the following is an incorrect match
A. Osmometer= measure rate of osmosis
B. Protometer= measure rate of transpiration
C. Porometer= measure area of stomata on the leaf
D. Cobait- chloride test= Comparision of transpiration by two surfaces of a leaf

Answer 1

Hint: Osmometer is used to measure the osmotic pressure.

Complete answer: The osmometer is a device that is used to measure the osmotic pressure of the solution. It is not used to measure the rate of osmosis
A protometer is also known as the transpirometer which is a device used for measuring the rate of water uptake in the leafy shoot which is the equal amount of water lost through transpiration.
A porometer is used to measure the area of stomata and the resistance on the stomatal leaves.
The cobalt chloride test is done for the comparison of transpiration by two surfaces of a leaf, it was first demonstrated by the scientist Stahl, as the cobalt chloride paper changes color from blue to pink when it comes in contact with the water.

Additional information: There are many different techniques involved in osmometry:
1. Vapor pressure osmometers find the concentration of osmotically active particles that lowers the vapor pressure of a solution.
2. Membrane osmometers measure the osmotic pressure of a solution separated from pure solvent through a semipermeable membrane.
3. Freezing point depression osmometers may be used to determine the osmotic strength of a solution, as osmotically active compounds lower the freezing point of a solution.

Hence, the correct option is ‘A’

Note: Osmometer is also used in the samples of urine and blood to determine the total concentration of the dissolved sugars and salts and is also used for the determination of molecular weights of unknown molecules.