Identify ether from the following compounds.

Ethers when dissolved in cold concentrated sulphuric acid forms

Identify the product '$$\mathrm{B}$$' in the following series of reactions.

$$\text { Propan - 1-ol } \xrightarrow[623 \mathrm{~K}]{\mathrm{Al}_2 \mathrm{O}_3} \mathrm{~A} \xrightarrow[\text { ii) } \mathrm{H}_2 \mathrm{O}]{\text { i) conc } \mathrm{H}_2 \mathrm{SO}_4} \mathrm{~B}$$

Which of the following alkyl halide is treated with sodium metal to obtain $$2,2,3,3$$ - tetramethyl butane?