Question

"The melting point of LiCl is higher than NaCl."Answer whether the above statement is true or false. If true enter 1, else enter 0.

Answer 1

Hint: Melting point of ionic compound is generally done by two factors:
1) Charge of the cation or anion.
2) Ionic Radius. Sometimes Fajan's rule also comes into picture and modifies the smooth going results. Fajans' rule is used to predict whether the chemical bond is covalent or ionic.

Complete step by step answer:
> The two major factors which play crucial role in determining the melting point of cation/anion are:
1.Charge of the cation or anion:
More the charge of cation or anion, stronger will be the force of attraction between the ions which leads to higher melting point.
2.Ionic radius:
- More the distance between ions, lesser will be the strength of the bond which gives rise to low melting point.
- But apart from these two major factors, sometimes we see the anomalous behavior in melting point, due to Fajan's rule. The size of LiCl is small and due to this it exhibits excessive polarization which leads to high covalent character in contrast to NaCl which is ionic in nature. We know that melting points of ionic compounds are higher than covalent compounds therefore, our answer will be 0.

Note: For solving these types of questions always remember that ionic compounds are formed from strong electrostatic interactions between ions, which results in higher melting points. On the other hand covalent compounds are formed by sharing electrons between atoms so, they have low melting point compared to ionic compounds