Question

2. 15 grams of CaCl is dissolved into 2 L of distilled water. (MW CaCl-110 g/mol) a. What is the osmolarity of this solution? b. What is the tonicity? e. What will happen to the shape of the cell if it is placed in this solution?

Answer 1

Ans 2 :

a)

Mol CaCl2 = mass /molar mass

= 15 g / 110.98 g/mol = 0.135 mol

each mol CaCl2 has three osmoles , so number of osmoles = 3 x 0.135 osmoles = 0.405 osmoles

Osmolarity = number of osmoles / volume (L)

= 0.405 osmoles / 2 L

= 0.203 osmol/L

b)

Since the membrane is not permeable to calcium and chlorine ions both so the tonicity of the solution is same as osmolarity i.e. 0.203 osmol/L

c)

The solution is hypotonic since it has less concentration of the solute particles in it. So when the cell is is placed in this solution , the cell swells up due to water absorption and hence it bursts if the wall is not rigid.