What percent concentration of KCl would be isotonic?

1 Answer
Jul 11, 2014

Answer:

Isotonic with what?

Explanation:

A 1.1 % (m/m) solution of KCl would be isotonic with blood.

Two solutions are isotonic if they have the same osmotic pressure or osmolality.

The normal osmolality of blood is about #"290 mOsmol/kg"# or #"0.29 Osmol/kg"#.

#"KCl" → "K"^+ + "Cl"^-#

#"1 mol KCl" = "2 Osmol"#

#(0.29 color(red)(cancel(color(black)("Osmol"))))/"1 kg" × (1 color(red)(cancel(color(black)("mol KCl"))))/(2 color(red)(cancel(color(black)("Osmol")))) × "74.55 g KCl"/(1 color(red)(cancel(color(black)("mol KCl")))) = "11 g KCl/kg"#

So there are #"11 g KCl"# in #"1000 g H"_2"O"#.

#"% KCl" = (11 color(red)(cancel(color(black)("g"))))/(1011 color(red)(cancel(color(black)("g")))) × "100 %" = "1.1 %"#