Due to $Schottky$ defect:

The incorrect statement regarding defects in crystalline solid is

Which defect leads to an increase in the density of a solid?

Why does table salt,$NaCl$,sometimes appear yellow in colour?

$A$ silicon specimen is made into a $p-$type semiconductor by doping,on an average,one indium atom per $5 \times 10^7$ silicon atoms. If the number density of atoms in the silicon specimen is $5 \times 10^{28} \ \text{atoms} \ m^{-3}$,then the number of acceptor atoms in silicon per cubic centimeter will be

Select the incorrect statement for Schottky defect.