Question

when nicl2 reacts with k2s,
a precipitate of nis is generated
b precipitate of kcl is generated
c precipitate of kcl2 is generated
d precipitate of ni2s is generated

Explanation:

Step1: Write the chemical reaction equation

The reaction between \(NiCl_2\) and \(K_2S\) is a double - displacement reaction. The general form of a double - displacement reaction is \(AB+CD = AD+CB\). Here, \(A = Ni^{2+}\), \(B = Cl^{-}\), \(C = K^{+}\), \(D = S^{2 -}\). So the reaction equation is \(NiCl_2+K_2S=NiS\downarrow + 2KCl\).

Step2: Analyze the solubility of products

According to solubility rules, most sulfides (\(S^{2-}\)) are insoluble in water except those of alkali metals (\(Li^{+},Na^{+},K^{+}\) etc.) and \(NH_4^{+}\). \(NiS\) is insoluble (forms a precipitate), while \(KCl\) is soluble in water (because salts of \(K^{+}\) and \(Cl^{-}\) are generally soluble). \(KCl_2\) and \(Ni_2S\) are not the correct chemical formulas for the products of this double - displacement reaction. The correct formula for nickel sulfide is \(NiS\) (since \(Ni\) has a \(+ 2\) charge and \(S\) has a \(-2\) charge in this compound) and for potassium chloride is \(KCl\) (\(K\) has a \(+1\) charge and \(Cl\) has a \(-1\) charge).

Answer:

A. precipitate of \(NiS\) is generated