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Question: Which is not a buffer solution? A. \(N{H_4}Cl\) +\(N{H_4}OH\) B. \(C{H_3}COOH\) +\(C{H_3}COONa\)...

Which is not a buffer solution?
A. NH4ClN{H_4}Cl +NH4OHN{H_4}OH
B. CH3COOHC{H_3}COOH +CH3COONaC{H_3}COONa
C. CH3COONH4C{H_3}COON{H_4}
D. NH4NO3N{H_4}N{O_3}

Explanation

Solution

A buffer solution either is a mixture of a weak acid and its salt with strong base or a mixture of a weak base and its salt with strong acid. So the solution which is not satisfying this condition is not a buffer solution.

Step by step answer: Let us first look at the buffer solution.
Buffer Solution: So buffer solution is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong base or acid is added to it.
So according to the above definition analyzing all the options
-1st is NH4ClN{H_4}Cl +NH4OHN{H_4}OH , in which NH4ClN{H_4}Clacts as a strong electrolyte and NH4OHN{H_4}OHacts as a weak electrolyte. Its dissociation is further suppressed by common ion NH4+NH_4^ + provided by NH4ClN{H_4}Clin the solution. This solution acts as a basic buffer and maintains its pH around 9.25. It is capable of resisting the change in pH in addition to a small amount of acid or alkali. So it is a buffer solution.
-2nd is CH3COOHC{H_3}COOH +CH3COONaC{H_3}COONa, which also acts as a buffer solution in the same way.
-3rd is CH3COONH4C{H_3}COON{H_4}which is not satisfying the above conditions so it is not a buffer solution so that is why it is a correct option.
-4th isNH4NO3N{H_4}N{O_3}, When in solution, ammonium nitrate will dissociate very well into NH4+NH_4^ + and NO3−NO_3^ - . The ammonium ion is a Bronsted-Lowry acid in that it will donate a H+{H^ + } to solution. In turn, this forms ammonia. Ammonia being a weak base will accept hydrogen ions from the solution, but not all of them. In conclusion, the solution will form equilibrium where the pH is slightly acidic due to H+{H^ + } ions being loose in solution. So according to the definition it is a buffer solution.

So the correct option is C.

Note: Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. In nature, there are many systems that use buffering for pH regulation. For example, the bicarbonate buffering system is used to regulate the pH of blood.