Ionic strength, μ, represents the total electrostatic forces contributed by ions in solution and can be calculated as shown in the following equation:
Where, Ci is the molar concentration of any ion in solution, and zi is its valence. Ionic strength is used to calculate activity and activity coefficient of ions and electrolytes in solution.
Example 1: Calculate ionic strength of a 0.02 M NaCl solution:
Answer: μ = 0.5[(0.02 × 12 ) + (0.02 × 12 )] = 0.02 M
Example 2: Calculate ionic strength of a 0.02 M BaSO4 solution:
Answer: μ = 0.5[(0.02 × 22 ) + (0.02 × 22 )] = 0.08 M
Example 3: Calculate ionic strength of a 0.02 M Na2SO4 solution:
Answer: μ = 0.5[(0.04 × 12 ) + (0.02 × 22 )] = 0.06 M
Example 4: Calculate ionic strength of a solution containing 0.02 M NaCl and 0.02 M BaSO4:
Answer: μ = 0.5[(0.02 × 12 ) + (0.02 × 12 ) + (0.02 × 22 ) + (0.02 × 22 )] = 0.10 M
Note: only ionized species contribute to ionic strength in solution.
Are you aware you have two question 2's?
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Deleteionic strength of 0.25 M CaCl2
ReplyDeleteionic strength=0.5[(0.25*2^2)+(0.5*1^2)]=0.75 M
Deletehow could i make a 10mM ionic strength cacl2 solution?
ReplyDelete10mM=0.5[(x*2^2)+(2x*1^2)] solve for x then x=3.33mM. A 3.33 mM solution of CaCl2 has ionic strength of 10mM according to this calculation.
Deletethank you
DeleteCalculate the ionic strength (M) of 50 ml of 0.75 % (w/v) NaCl solution?
ReplyDelete