Question

the activity of "M" molal of CuSo4 solution can be expressed in term of its activity coefficient (y+-) as​

Answer 1

calculating the mean activity coefficient #gamma_pm#, for solutions with concentrations on the order of #0.01 M# or less, is:

#\mathbf(log gamma_pm = (1.824xx10^6)/(epsilonT)^"3/2"|z_+z_-|sqrtI)#

where #epsilon# is the dielectric constant, #z_pm# is the charge of each ion, and of course, #T# is temperature in #K#. #I# is the ionic strength, defined as:

#\mathbf(I = 1/2 sum_i m_i z_i^2)#

where #m# is the molality and #z# is the charge (here, the sign doesn't matter).

In water, #epsilon = 78.54#. I don't know what temperature you are referring to, but I will assume #T = "298 K"#.

In #Ba(HCO_3)_2#, you have the ions #Ba^(2+)# and #HCO_3^(-)#. Thus, #z_(+) = "+2"# and #z_(-) = "-1"#.

Explanation:

calculating the mean activity coefficient #gamma_pm#, for solutions with concentrations on the order of #0.01 M# or less, is:

#\mathbf(log gamma_pm = (1.824xx10^6)/(epsilonT)^"3/2"|z_+z_-|sqrtI)#

where #epsilon# is the dielectric constant, #z_pm# is the charge of each ion, and of course, #T# is temperature in #K#. #I# is the ionic strength, defined as:

#\mathbf(I = 1/2 sum_i m_i z_i^2)#

where #m# is the molality and #z# is the charge (here, the sign doesn't matter).

In water, #epsilon = 78.54#. I don't know what temperature you are referring to, but I will assume #T = "298 K"#.

In #Ba(HCO_3)_2#, you have the ions #Ba^(2+)# and #HCO_3^(-)#. Thus, #z_(+) = "+2"# and #z_(-) = "-1"#.