What is the molarity of the chloride ions in a #"0.230 M NaCl"# solution?

1 Answer
Jan 31, 2015

The molarity of chloride ions is #"0.230 M"# or #"0.230 mol/L"#.

Explanation:

You have been given the molarity of the solute #"NaCl"# as #"0.230 M"#, which means #"0.230 mol NaCl/L"#.

The next step is to determine the ion to solute ratio, by doing the following:

NaCl dissociates by the reaction:

#"NaCl"# #rarr# #"Na"^(+) + "Cl"^(-)"#

#"ion/solute"# = #"mol Cl"^(-)"/mol NaCl"# = #"1 mol Cl"^(-)"/1 mol NaCl"#

Next determine the molarity of the #"Cl"^(-)" ion"#.

#"M Cl"^(-)"##=##"M NaCl"##xx##"ion/solute ratio"#

#"M Cl"^(-)## = ##(0.230color(red)cancel(color(black)( "mol NaCl")))/"L"xx("1 mol Cl"^(-))/(1color(red)cancel(color(black)(" mol NaCl")))#

#"M Cl"^(-)## = ##"0.230 mol Cl"^(-)"/L"## = ##"0.230 M Cl"^(-)"#

http://chemistry.about.com/od/workedchemistryproblems/a/Molarity-Of-Ions-Example-Problem.htm