Assume a living cell with 0.9% (w/w) of glucose solution (aqueous). This cell is immersed in another solution having equal mole fraction of glucose and water. (Consider the data upto first decimal place only) The cell will :
- shrink since solution is 0.45% (w/w) as a result of association of glucose molecules (due to hydrogen bonding)
- shrink since solution is 0.5% (w/w)
- show no change in volume since solution is 0.9% (w/w)
- swell up since solution is 1% (w/w)
Answer
Solution
Outside solution: equal mole fractions nglucose = nwater.
Take 1 mol of each: mass of glucose = 180 g, mass of water = 18 g.
% (w/w) of glucose = 180180 + 18 100 = 90.9\%
Cell sap: 0.9% (w/w) glucose, i.e. xglucose = 0.9/1800.9/180 + 99.1/18 9 10-4.
The outside solution is far more concentrated (hypertonic); water moves out of the cell by osmosis and the cell shrinks.
None of the options gives the correct concentration of the outside solution (90.9% w/w), so no option is fully correct; the question was awarded as bonus.
Answer: No option is correct (the cell shrinks).