Chemistry - Complete s-block Question with Solution | TestHub
Covalent character in ionic bond is compared with the help of Fajan's rule. According to Fajan's rule as polarising power of cation and polarisibility of anion increases covalent character in ionic bond increases on that basis we compare various properties of molecule. Solubility primarily depends on hydration and lattice energy and thermal stability primarily depends on covalent nature and lattice energy depending on type of anion in the salt. On the other hand, melting point increases with lattice energy and decreases with covalent nature.
Answer the following by appropriately matching the lists.
Column I (Radicals) | Column II (Property having increasing order down the group) |
|---|---|
(P) Perchlorates of Alkali metals | (1) Melting point |
(Q) Chlorides of Alkali metals | (2) Lattice energy |
(R) Fluorides of Alkaline earth metals | (3) Thermal stability |
(S) Hydroxides of Alkaline earth metals | (4) Solubility in H2O |
| (5) Covalent character |
| (6) Ionic character |
Which of the following is an INCORRECT match?
Options:
Answer:
Solution:
(A) Perchlorate stability and ionic character both rise down the group: correct.
(B) Alkali chloride melting points: LiCl 605, NaCl 801, KCl 770, RbCl 718, CsCl 646 °C. They do not keep rising: incorrect.
(C) Hydroxide solubility and ionic character rise: correct.
(D) Hydroxide solubility and thermal stability rise: correct.
Answer: (B).
