Final answer:
To determine the SN₂ reaction products, the concept of nucleophilic substitution is applied, with substituting groups or atoms leading to the formation of new compounds. SN₂ reactions provided form various complexes through the replacement process. For double replacement and other reactions at equilibrium, the direction of the shift is dictated by Le Chatelier's principle in response to changes in concentration, pressure, or temperature.
Step-by-step explanation:
To determine the products of each SN₂ reaction, we must understand the concept of a nucleophilic substitution, where the nucleophile replaces another group or atom in the molecule. For reaction b, SnS₂ + S²⁻ → SnS⁻, tin(IV) sulfide reacts with the sulfide anion resulting in tin(II) sulfide. Reaction c, Cd(CN)₂ + 2 CN⁻ → Cd(CN)⁴²⁻, involves cadmium cyanide reacting with cyanide ions yielding a complex containing cadmium with a charge of negative 2. In reaction d, AgCl +2 NH₃ → Ag(NH₃)₂⁻ + Cl⁻, silver chloride reacts with ammonia to form a coordination complex of silver with ammonia and a chloride ion.
Moving to reactions outside the SN₂ type, for example, Fe²⁻ + NO → Fe(NO)²⁻ represents a complexation reaction where iron(II) forms a complex with nitric oxide. Lastly, Ni²⁻ + 6 NH₃ → Ni(NH₃)⁶²⁻ shows the formation of a hexaamminenickel(II) complex.
For double replacement reactions, such as N₂ + 3H₂ → 2NH₃, if we consider Le Chatelier's principle and a system at equilibrium, adding hydrogen gas (H₂) would shift the reaction towards the products, generating more ammonia (NH₃). Conversely, adding a product like NH₃ would shift the equilibrium towards the reactants. If the reaction is exothermic, adding heat would also push the equilibrium towards the reactants.