(A) Ether behaves as bases in the presence of mineral acids.
(R ) Due to the presence of lone pair of electrons on oxygen.

Options

A. If both the assertion and reason are true and reason is correct explanation of the assertion .
B. If both the assertion and reason are true but reason is not a correct explanation of the assertion .
C. If the assertion is true but the reason is false.
D. If both assertion and reason are false.

Explanation

To solve the assertion and reasoning question regarding ethers and their behavior in the presence of mineral acids, we can break it down into clear steps:

### Step-by-Step Solution:

1. **Understanding Ethers**:
- Ethers have the general formula R-O-R', where R and R' are alkyl groups. The oxygen atom in ethers has two lone pairs of electrons.

2. **Definition of Mineral Acids**:
- Mineral acids are strong acids, such as hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3). These acids completely ionize in solution.

3. **Behavior of Ethers with Mineral Acids**:
- When ethers are treated with strong mineral acids, they can act as bases. This is because the lone pairs of electrons on the oxygen atom can accept protons (H+ ions) from the acid.

4. **Formation of Oxonium Ion**:
- For example, when an ether reacts with HCl, the lone pair on the oxygen atom can bond with a proton (H+) from the acid, leading to the formation of an oxonium ion (R-OH2+). This reaction can be represented as:
\[ R-O-R' + HCl \rightarrow R-OH2^+ + R'Cl \]
- In this reaction, the ether behaves as a base by accepting a proton.

5. **Conclusion**:
- Since ethers can accept protons due to the presence of lone pairs on the oxygen atom, they behave as bases in the presence of mineral acids. Therefore, both the assertion (A) and the reason (R) are true, and the reason correctly explains the assertion.

### Final Answer:
Both assertion and reason are true, and the reason is the correct explanation of the assertion.