Which equations represent precipitation reactions? na2s + febr2 → 2nabr + fes mgso4 + cacl2 → mgcl2 + caso4 lioh + nh4i → lii + nh4oh 2nacl + k2s → na2s + 2kcl agno3 + nacl → agcl + nano3

A. : In this reaction one of the product, FeS is insoluble. Therefore, this is a precipitation reaction.

B. : In this reaction, the product is a solid(insoluble). So, this is a precipitation reaction too.

C.: In this reaction, both the products are soluble. So this is not a precipitation reaction.

D.: In this reaction, both the products are soluble. So this is not a precipitation reaction.

E. : In this reaction, the product AgCl is a precipitate. So, it is a precipitation reaction.

Answer : The correct option is,

Explanation :

Precipitation reaction : It is defied as the chemical reaction in which the two soluble salts solutions combined to form an insoluble salts.

(1)

(2)

(3)

(4)

(5)

In the given reactions 1, 2, 3 and 4, the salt forms are completely soluble in water.

As we know that all the sodium, potassium and ammonium salts are soluble in water.

While in the reaction 5, the salt form that is silver chloride (AgCl) are insoluble in water. So, this reaction is a precipitation reaction.

Hence, the correct option is,

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).