Question

Identify buffer solutions from the following list. (Please explain answer)

Choose all that apply.

0.21 M hydrocyanic acid + 0.19 M sodium cyanide
.

0.26 M perchloric acid + 0.17 M sodium perchlorate
.

0.14 M barium hydroxide + 0.30 M barium chloride
.

0.34 M barium iodide + 0.27 M barium chloride
.

0.31 M ammonia + 0.30 M ammonium nitrate
.

Answer 1

Answer:

A buffer solution is made up of weak acid and salt of it's conjugate base or weak base with it's salt of conjugate acid.

(1) 0.21 M hydrocyanic acid (HCN) + 0.19 M sodium cyanide (NaCN)

Here HCN is weak acid and it's conjugate base is CN^-.

And NaCN is sodium salt of CN^-.

So it a buffet solution.

(2) 0.26 M perchloric acid (HClO4) + 0.17 M sodium perchlorate (NaClO4).

Here HClO4 is strong acid and NaClO4 is sodium salt of ClO4^-.

So it is not a buffer solution.

(3) 0.14 M barium hydroxide (Ba(OH)2) + 0.30 M barium chloride (BaCl2).

Here Ba(OH)2 is strong base so it is also not a buffer solution.

(4) 0.34 M barium iodide (BaI2) + 0.27 M barium chloride(BaCl2).

Here BaI2 and BaCl2 are salts. So it is not buffer solution.

(5) 0.31 M ammonia (NH3) + 0.30 M ammonium nitrate (NH4NO3)

Here NH3 is weak base and NH4^+ is it's conjugate acid.

And NH4NO3 is nitrate salt of ammonia.

Therefore it is buffer solution.

Finally

0.21 M hydrocyanic acid + 0.19 M sodium cyanide

And

0.31 M ammonia + 0.30 M ammonium nitrate
are buffer solutions.

Please let me know if you have any doubt. Thanks