Which of the following pairs of substances, when mixed in any proportion you wish, can be used to prepare a buffer solution?
1)NaCN and NaOH
2) HCl and NaOH
3) HCN and NaOH
4)HCl and NaCN
5) NaCN and HCN
is the answer 1 and 5??
chem - DrBob222, Sunday, April 10, 2011 at 1:28am
I don't believe 1 will do it.
Yes on 5. Also 3.
Buffers are weak acid and salt or weak base and salt.
HCN and NaOH can prepare the salt and have HCN left over.
NaCN is the salt HCN for the acid.
chem - Rachel, Sunday, April 10, 2011 at 2:18pm
I tried those and it was wrong
5 can be made to a buffer. 3 can be made to a buffer. That means there must be another one since I assume you are keying this into a data base and you must have ALL of the problem right or it is counted wrong. I would look for another one if I were you. By the way, you KNOW 2 can't be one of them.
To answer this question, we need to understand the concept of buffer solutions. A buffer solution is a solution that resists changes in pH when small amounts of acid or base are added to it.
To prepare a buffer solution, we need a weak acid or base and its conjugate salt. In the given options, we have:
1) NaCN and NaOH: NaCN is the conjugate salt of the weak acid HCN. However, NaOH is a strong base and does not form a buffer solution with NaCN.
2) HCl and NaOH: Both HCl and NaOH are strong acids and bases, respectively. Therefore, this pair cannot be used to prepare a buffer solution.
3) HCN and NaOH: HCN is a weak acid and NaOH is a strong base. This pair can be used to prepare a buffer solution as HCN can act as a weak acid and NaCN can act as its conjugate salt.
4) HCl and NaCN: Both HCl and NaCN are strong acids and bases, respectively. Therefore, this pair cannot be used to prepare a buffer solution.
5) NaCN and HCN: NaCN is the conjugate salt of the weak acid HCN. This pair can be used to prepare a buffer solution as HCN can act as a weak acid and NaCN can act as its conjugate salt.
From the given options, the correct pairs of substances that can be used to prepare a buffer solution are 3) HCN and NaOH and 5) NaCN and HCN.