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Homework Help: Which of the following solutions result in a buffer ?

  1. Mar 11, 2007 #1
    1. The problem statement, all variables and given/known data

    2. [1pt]

    Which of the following solutions result in a buffer ?



    a) 0.100 L of 0.250 M NH3 + 0.050 L of 0.250 M HCl


    b) 0.100 L of 0.250 M NH3 + 0.100 L of 0.250 M HCl


    c) 0.100 L of 0.250 M NH4Cl + 0.050 L of 0.250 M NaOH


    d) 0.100 L of 0.250 M NH4Cl + 0.150 L of 0.250 M NaOH



    2. Relevant equations

    M = mol/V

    3. The attempt at a solution

    so I got the mol for each one, they are

    1) .025 mol and .0125 mol
    2) .025 mol and .025 mol
    3) .025 mol and .0125 mol
    4) .025 mol and .0375 mol

    I don't know how to do it, plz help help
     
  2. jcsd
  3. Mar 11, 2007 #2

    symbolipoint

    User Avatar
    Homework Helper
    Education Advisor
    Gold Member

    Simply check which situation conforms to the definition of a pH buffer. You first know that ammonium and chloride are "completely" ionized in water solution. Now, in which solution exists either a weak base and salt of that base; or an weak acid and a salt of that acid?
     
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