Homework Help: chem

Posted by Rebekah on Sunday, April 10, 2011 at 7:19pm.

Which of the following pairs of substances, when mixed in any proportion you wish, can be used to prepare a buffer solution? (Select all that apply.)

NaCN and HCN
NaCN and NaOH
HCN and NaOH
HCl and NaCN
HCl and NaOH

I thought it was the middle three because each either has a strong base or strong acid but its wrong.

How are you suppose to know?
thans

chem - DrBob222, Sunday, April 10, 2011 at 11:52pm
Here is a site to read about buffers. Note the table of buffers.
http://en.wikipedia.org/wiki/Buffer_solution

Based on the link above, NaCN and HCN (1) would qualify as a buffer since it is a weak acid (HCN) and its conjugate base (CN^-). HCl and NaCN (4) will qualify in most cases although HCl is not a weak acid but it produces HCN when reacted with NaCl to produce the weak acid, HCN. HCN + NaOH (3) will qualify because it produces NaCN in the reaction. HCl and NaOH do not qualify because that is a strong acid and strong base and NaCl is a salt of either a weak acid or a weak base. That leaves only reaction 2 for you to ponder.

Answer this Question

Related Questions

chem - Which of the following pairs of substances, when mixed in any proportion ...
chem - Which of the following pairs of substances, when mixed in any proportion ...
Chemistry (repost) - Which of the following pairs of substances, when mixed in ...
chemistry - Which of the following pairs can be used to prepare a buffer? (...
Chemistry - You need to prepare 100.0 mL of a pH=4.00 buffer solution using 0....
science - Which pairs of substances will form a buffer when mixed in equal ...
chemistry - Which of the following substances can act as a Bronsted acid in ...
Science - Which pairs of substances will form a buffer when mixed in equal ...
chemistry - Choices: True,False. Select all that are True. The pH at the ...
Chemistry - Q1: You wish to prepare a buffer solution with pH = 11.10. What ...

For Further Reading

First Name:
School Subject:
Answer: