#!/usr/local/bin/perl # This is just a cgi generated HTML submission form. You can do the same # thing with HTML, but for the sake of distribution, I am doing it this way # so that all the files can remain together. # The only thing tricky about the FORM which you use as your user # interface is that each radio multiple choice button series must have NAME # argumnets corresponding to the first field in the answers database. # Also, the VALUE must correspond exactly to the corresponding field in the # answers database. # First print out the HTTP headcer, then print out the form print "Content-type: text/html\n\n"; print qq! Multiple Choice: Acid Base Reactions
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Several different reactions are used to get information about pH and reagent concentration when working with buffer solutions or acid/base titrations. Consdier the following reactions:

a) HA + H2O <---> A- + H3O+
c) B + H2O <---> BH+ + OH-
b) HA + OH- <---> A- + H2O
d) B + H3O+ <---> BH+ + H2O

1. A 0.1 M solution of a weak acid (HA) is combined with a 0.05 molar solution its conjugate base (A-). To find the pH of the solution use
reaction a.
reaction b.
reaction c.
reaction d.

2. 100 mL of a 0.1 M solution of a weak base B are titrated with 0.1 M HCl. To find the pH after 5 mL of HCl have been added use
reaction a.
reaction c.
reaction d to determine the moles of weak base which react with the weak acid followed by reaction c to determine the pH.
reaction c to determine the moles of weak base which react with the weak acid followed by reaction d to determine the pH.

3. The reaction which would give information about the pH of a buffer composed of ammonia (pKb=4.74) and ammonium chloride is
reaction a.
reaction b.
reaction c.
reaction d.

4. The reaction which would give information about the pH of a titration of a weak acid with a strong base after the stoiciometric point would be
reaction a.
reaction b.
reaction c.
none of the above.

5. A buffer is made from 10.0 mL of 0.1 M NH3 and 10.0 mL of 0.1 M NH4Cl. 0.001 mole of HCl is added to the solution. To find the pH of the new solution use
reaction a followed by reaction b.
reaction d followed by reaction c.
reaction c followed by reaction d.
reaction d.

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