Major products formed in the reaction of tert-butyl methyl ether with $\mathrm{HI}$ are:

What are $\mathrm{P}$ and $\mathrm{Q}$?

In the above reaction, the product $\mathrm{D}$ will be

What is $\mathrm{X}$ in the following change?

The total number among following ethers which cannot be prepared by Williamson's synthesis is:

${\mathrm{CH}}_3{\mathrm{OCH}}_2{\mathrm{CH}}_3, {\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{OCH}}_3, {\left({\mathrm{C}}_6{\mathrm{H}}_5\right)}_2\mathrm{O}, {\left({\mathrm{CH}}_3\right)}_3{\mathrm{COCH}}_3, {\left({\mathrm{C}}_2{\mathrm{H}}_5\right)}_2\mathrm{O}, {\left({\mathrm{CH}}_3\right)}_3\mathrm{C}-\mathrm{O}-\mathrm{C}{\left({\mathrm{CH}}_3\right)}_3$