Question

you may have noticed an (s) next to one of the products in some double replacement reactions. an (s) next to a compound signifies that it is an insoluble solid, also know as a precipitate. precipitates can be either cloudy or chunky substances of various colors in an ionic solution. to predict if a product in a double replacement reaction forms a precipitate, you need to use the solubility rules found here. for each reaction below, use the drop - down menus to select which compound will form a precipitate. note: it is possible that no precipitates form. na₂s + cd(no₃)₂ → cds + 2nano₃ fecl₃ + 3koh → 3kcl + fe(oh)₃ na₂co₃ + ba(no₃)₂ → baco₃ + 2na

Explanation:

Step1: Analyze solubility of products

For the reaction $\ce{Na_{2}S + Cd(NO_{3})_{2} -> CdS + 2NaNO_{3}}$, we use solubility rules. Sodium nitrate ($\ce{NaNO_{3}}$) is soluble (nitrates are generally soluble, and sodium salts are soluble). Cadmium sulfide ($\ce{CdS}$) is insoluble (sulfides of most transition metals like Cd are insoluble).

Step2: Determine precipitate

From the solubility analysis, $\ce{CdS}$ (cadmium sulfide) is the insoluble solid (precipitate), while $\ce{NaNO_{3}}$ is soluble.

Answer:

cadmium sulfide