Question

Name a salt prepared by precipitation reaction. What property must it exhibit?

Answer 1

First we know that precipitation reactions occur when cations and anions in aqueous solution (solution containing soluble salts) combine to form an insoluble salt (ionic solids). This insoluble salt is called a precipitate.The precipitation reaction used to determine the presence of various ions in solution.

Complete answer:
Barium sulphate is not soluble in water because the lattice energy of barium sulphate is more than the enthalpy of solvation due to largest size of anion and cation. Barium sulphate is an inorganic compound chemical formula is $BaS{O_4}$.
Hence Barium sulphate salt is made of $B{a^{2 + }}$ ions and $S{O_4}^{2 - }$ ​ ions.
To prepare insoluble barium sulphate salt, we have to prepare two soluble solutions (salts solutions) of which one contains $B{a^{2 + }}$, its positive metal ions and the other contains the $S{O_4}^{2 - }$, its negative non-metal ions. These two ions will react and form precipitate known as barium sulphate. Its chemical reaction can be written as follows
$B{a^{2 + }}(aq) + S{O_4}^{2 - }(aq) \to BaS{O_4}(s)$
The precipitate barium sulphate salt is separated from solution by various methods, such as filtration, centrifuging, etc.
The precipitate reactions (where precipitate is one of the products) depends on some determining factors. Some reactions depend on temperature, some reactions are depending only on solution concentration.

Note:
The solids produced in precipitate reactions are crystalline solids and can be suspended throughout the liquid or fall to the bottom of the solution. The remaining fluid is called supernatant liquid.
Barium sulphate is used as a radiopaque agent and used in the casting of copper anode plates as a coating material. It is used to test the pH of the soil. It is used in the manufacturing of alloys.