Question

A cell placed in 100 mM NaCl would?
a. absorb water and lyse
b. lose water and shrink
c. not change in volume

Answer 1

ANS: a

In normal cells do have isotonic concentration means 0.9 % NaCl it is corresponding to 155 mM ( if you take weight 0.9 grams dissolved in 100 ml H2O it will be 155 mM).

In our problem your keep a cell in 100 mM NaCl solution means it is a hypotonic solution means the concentration of solute lesser than in biological cell (155 mM). Then the water enters into biological cell (osmasis) to dilute the high concentration of NaCl leads increase volume of cell, absorb water from outside solution and burst or lyse the cell.