First, we must know what happens in the precipitation reaction. This type of reaction is a double replacement reactions. It is consists of two reactant compounds which interchange cations and anions to form two products. One of the products is an insoluble solid called a precipitate. For the precipitation of CaCO₃, there are two consecutive reactions involved:
1. Slaking of quicklime, CaO
CaO + H₂O ⇒ Ca(OH)₂
2. Precipitation
Ca(OH)₂ + CO₂ ⇒ CaCO₃ + H₂O
The ions that make up the H₂O molecule are H⁺ and OH⁻. According to solubility rules, the cation (positively charged ion) is likely to be attracted to an anion (negatively charged ion). Together, they form an ionic bond. This type of bond is when there is a complete transfer of electrons between the two. The Ca²⁺ cation lacks 2 electrons, while the anion OH⁻ has an excess 1 electron. In order to be stable, 1 Ca²⁺ ion and 2 OH⁻ ions must combine.
Therefore, the answer is OH⁻ ion.
Answer :
(A) Br₂ (s) : molecular solids
(B) AgCl (s) : ionic solids
(C) S (s) : atomic solids
(D) CH₄ (s) : molecular solids
Explanation :
Molecular solids : It is defined as the solids in which they are held together by covalent forces, dipole interactions as attractive forces etc.
Ionic solids : It is defined as the solids in which the atoms composed with oppositely charged ions.
Atomic solids : It is defined as the solids in which the molecules are held together by covalent forces and also includes pure substance.
(A) Br₂ (s)
It is molecular solids because they are held together by covalent forces.
(B) AgCl (s)
It is ionic solids because in this atoms composed with oppositely charged ions.
(C) S (s)
It is atomic solids because it is a pure substance.
(D) CH₄ (s)
It is molecular solids because they are held together by covalent forces.
Answer:
Different Number of neutrons.
