Question

When $LiN{O_3}$ is heated, it gives oxide, $Li{O_2}$ , whereas other alkali metal nitrates decomposes to give corresponding:
A.Nitrite
B.Peroxide
C.Both oxide and nitrite
D.None of these

Answer 1

Hint:Alkali metals are the s-block metals that are lithium, potassium, sodium, rubidium and caesium. Alkali metal nitrates are simply the chemical compound consisting of an alkali metal and the nitrate ion. Lithium is different from other alkali metals due to its extremely small size.

Complete answer:
Lithium is very small in size. In more exact words, atomic size of lithium is very small as compared to others in the family of alkali metals. When the nitrate of lithium is heated the following reaction takes place:
$4LiN{O_3}\xrightarrow{\Delta }2Li{O_2} + 4N{O_2} + {O_2}$
Lithium oxide and nitrite is formed. But in case of other alkali metal nitrates, they decomposes to give corresponding nitrite only, this dissimilarity is due to the extremely small size of lithium ion that is $L{i^ + }$ , it is very polarizing and hence favors the production of lithium oxide that is $Li{O_2}$ .
In case of other alkali metal only corresponding nitrite is formed and the reaction followed as:
$MN{O_3}\xrightarrow{\Delta }MN{O_2} + \dfrac{1}{2}{O_2}$

So, Option A is correct.

Note:
Alkali elements show a regular trend in their properties among their respective group elements. But the first member of both s-block elements that are Lithium and Beryllium differ from the other members of the family but they show similar property with the diagonal element present in the next column. That’s why these two elements have anomalous properties. This dissimilarity is due to Low atomic and ionic size of lithium and beryllium and also due to Greater charge density, Greater polarization and Absence of d-orbitals.
Due to the high polarization of s-block elements makes the first element more covalent and differentiates them from the rest which are ionic.
The similarity in size and charge density makes them similar to the element diagonally placed in the next group (diagonal relationship).