A : The number of spheres are equal to the number of octahedral voids as well as tetrahedral void.
R : Octahedral void and tetrahedral void has equal size.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To analyze the statements provided in the question, we will break down the concepts of octahedral and tetrahedral voids in the context of a crystal lattice.

### Step-by-Step Solution:

1. **Understanding the Number of Voids**:
- In a crystal lattice, the number of octahedral voids is equal to the number of atoms (spheres) present in the lattice. For example, if there are Z atoms in the unit cell, there will also be Z octahedral voids.
- However, the number of tetrahedral voids is not equal to the number of atoms. Instead, it is twice the number of atoms in the unit cell. Therefore, if there are Z atoms, there will be 2Z tetrahedral voids.

**Conclusion**: The statement "the number of spheres are equal to the number of octahedral voids as well as tetrahedral voids" is **false** because the number of tetrahedral voids is double that of the spheres.

2. **Comparing Sizes of Voids**:
- The size of the octahedral void and tetrahedral void is not the same. The radius ratio for tetrahedral voids (the ratio of the radius of the cation to the radius of the anion) should be between 0.225 and 0.414 for stability.
- In contrast, the radius ratio for octahedral voids should be greater than 0.414 and can go up to 0.732.

**Conclusion**: The statement "octahedral void and tetrahedral void has equal size" is also **false** because their size ratios differ significantly.

3. **Final Evaluation**:
- Since both statements A and R are false, the correct answer is that both A and R are incorrect.