Which of the following statement is not true about the hexagonal close packing?
(i) The coordination number is 12.
(ii) It has 74% packing efficiency.
(iii) Tetrahedral voids of the second layer are covered by the spheres of the third layer.
(iv) In this arrangement spheres of the fourth layer are exactly aligned with those of the first layer.
The answer is the option (iv).
Hexagonal packing has layers arranged in ABAB pattern. The spheres of first layer are aligned with the third layer and not the fourth layer.
The 1st layer and 4th layer are not exactly aligned. Thus, statement (d) is not correct while other statements (a), (b) and (c) are true.