Which of the following is a precipitation reaction?

a. 2 LiI (aq) + Hg2 (NO3) 2 (aq) →Hg2I2 (s) + 2 LiNO3 (aq)

b. NaCl (aq) + LiI (aq) → NaI (aq) + LiCl (aq)

c. HCl (aq) + KOH (aq) → KCl (aq) + H2O (l)

d. Zn (s) + 2AgNO3 (aq) → 2 Ag (s) + Zn (NO3) 2 (aq)

e. None of the above areprecipitation reactions.

The precipitated are option a and d.

Explanation:

2 LiI (aq) + Hg2 (NO3) 2 (aq) → Hg2I2 (s) ↓ + 2 LiNO3 (aq)

Cation Hg2 + 2 in the presence of iodide, a precipitated is formed.

Zn (s) + 2AgNO3 (aq) → 2 Ag (s) ↓ + Zn (NO3) 2 (aq)

Zinc starts to get rid, and some white particles also stick to it. Afterwards the solution becomes cloudy and a precipitate appears, which is the solid silver