(1) Frenkel defect is usually favoured by a very small difference in sizes of cation and anion
(2) Frenkel defect is a dislocation defect
(3) Trapping of an electron in the lattice leads to formation of F-Center
(4) Schottky defects have no effect on physical properties of solids
(1)and(2)(2)and(3)(3)and(4)(2)and(4)