JEE Main levelSingle correct optionDifficulty 2 of 3ss152
Assertion (A): Ionic solids are hard and brittle.
Reason (R): Ionic solids are held by strong electrostatic forces and a shift of layers brings ions of like charge face to face, which causes repulsion and cleavage.
Choose the correct option.
ABoth A and R are true and R is the correct explanation of A
BBoth A and R are true but R is not the correct explanation of A
CA is true but R is false
DA is false but R is true
Answer: A
Strong Coulombic forces make ionic solids hard. When a layer is displaced by about half a lattice spacing, like charges are brought adjacent and repel, so the crystal breaks rather than deforms. R correctly explains A.