Question

Arrange the following in ascending order based on their solute concentration

Cell	Water potential (KPa)	Pressure potential (KPa)
a	-590	320
b	-368	623
c	-292	412
d	-481	146

A) a, a ,d, b
B) d, c, a, b
C) a, c, b, d
D) b, a, c, d

Answer 1

Hint: Water potential can be defined as the energy required in a device relative to pure water when both pressure and temperature are conserved. It is found by adding pressure potential and solute potential.

Complete answer:
Water potential (KPa) can be defined as the potential energy of water per unit volume relative to pure water in reference conditions. Pressure potential is also called turgor potential or turgor pressure and is represented by Ψp. It is usually positive.
>Option A: The solute potential of the cells a,b,c, and d are -910, -991, -704, -627 respectively. The cell having the lowest value of the solute potential has the highest solute concentration. So, the order of the solute concentration of cells in the given option is wrong. Therefore, this is an incorrect option.
>Option B: The cell having the lowest value of the solute potential has the highest solute concentration. The solute potential of the cells a,b,c, and d are -910, -991, -704, -627 respectively. So, the arrangement of cells in the ascending order with respect to the solute concentration is wrong. Therefore, this is an incorrect option.
>Option C: The cell having the lowest value of the solute potential has the highest solute concentration. The solute potential of the cells a,b,c, and d are -910, -991, -704,-627 respectively. So, the arrangement of cells in the ascending order with respect to the solute concentration is wrong. Therefore, this is an incorrect option.
>Option D: Water potential = Pressure potential + Solute potential. Therefore, solute potential = water potential - pressure potential. Hence, the solute potential of the cells a,b,c, and d are -910, -991, -704, -627 respectively. The cell having the lowest value of the solute potential has the highest solute concentration. So, the solute concentration of cells a,b,c,d in ascending order will be b, a,c,d. Therefore, this is the correct option.
Hence the correct answer is option ‘D’.
Note: It is to be noted that the solute potential also called osmotic potential, is negative in a plant cell and zero in distilled water. Also, please take care while adding and also please take in consideration of the different signs.