Question

Which stoichiometric defect increases the density of a solid?

Answer 1

Hint: Before attempting this question one must have prior knowledge about the stoichiometric defect and the types of stoichiometric defects such as Schottky defect and Frenkel defects, use this information to approach towards the solution to the question.

Complete step by step solution: Before approaching towards the solution let’s discuss about the stoichiometric defect and the type of stoichiometric defects
So the concept of stoichiometric defect can be explained as the defect which doesn’t change the numbers of positive ions and numbers of negative ions ratio of any compound is named as stoichiometric defect.
It is of two types one is vacancy defect and interstitial here in vacancy defect in a compound an atom is not present at their lattice sites due to which the lattice site remains vacant and thus it creates a vacancy defect in compound and interstitial defect is other type of stoichiometric defect in which intermolecular spaces in compounds gets occupied by the atoms or molecules due to which the density of the compound increases.

Hence by the above statement we can say that interstitial defect is a type of stoichiometric defect in which density of solid increases.

Note: In the above solution the defects vacancy and interstitial defect is only shown by the non-ionic compounds and the ionic compounds shows defects like Frenkel and Schottky defect which can be explained as in Frenkel defect a cation or anion in a compound moves from its position and moves to the intermolecular free space inside the compound. In this defect the density of compounds remains the same.
Schottky defects generally found in ionic compounds which contain lesser amounts of ions in comparison to perfect crystals so to maintain the electrical neutrality in compound anions and cations of equal numbers leave the compound due to which the density of the substance decreases.