Assertion : A tetrahedral void is surrounded by four spheres and an octahedral void is surrounded by six spheres.
Reason : In hcp or ccp the number of tetrahedral voids is double the number of close packed spheres and number of octahedral voids is equal to number of close packed spheres.

Options

A. If both (A) and ( R) are correct and ( R) is the correct explanation of(A).
B. If both (A) and ( R) are correct, but ( R) is not the correct explanation of (A).
C. If (A) is correct, but ( R) is incorrect.
D. If both (A) and ( R) are incorrect.

Answer

B

Explanation

Tetrahedral voids are called so because a tetrahedron is formed when the centres of the four spheres are joined, while octahedral voids form octahedron when centres of surrounding six spheres are joined.