Question

Unit 3 4, If we are to minimize the total number of chloride ions impacting the environment upon ap- plication of road salt in the winter, which would be better to use on the roadss.a 23 w/w% sodium chloride solution or a 23 w/w% calcium chloride solution? Show calculations to explain your choice! trying

Answer 1

It would be better to use the NaCl solution.

Step-by-step explanation:

We can calculate the amount of Cl⁻ in each salt.

NaCl

Taking into account the molar masses, there are 35.5 g of Cl⁻ every 58.5g of NaCl. So, for a 23 w/w% solution of NaCl:

`(23gNaCl)/(100gSolution) .(35.5gCl^(-) )/(58.5gNaCl) =(14.0gCl^(-) )/(100gSolution) = 14.0w/w \%`

CaCl₂

Taking into account the molar masses, there are 71.0 g of Cl⁻ every 111g of CaCl₂. So, for a 23 w/w% solution of CaCl₂:

`(23gCaCl_(2))/(100gSolution) .(71.0gCl^(-) )/(111gCaCl_(2)) =(14.7gCl^(-) )/(100gSolution) = 14.7w/w \%`

The concentration of Cl⁻ in the NaCl solution is 14.0 w/w% and its concentration in the CaCl₂ solution is 14.7 w/w%, so we would choose the NaCl solution to minimize Cl⁻ concentration.