Grignard reagent $\mathrm{RMgBr}(\mathrm{P})$ reacts with water and forms a gas $(\mathrm{Q})$. One gram of Q occupies $1.4 \mathrm{dm}^3$ at STP. (P) on reaction with dry ice in dry ether followed by $\mathrm{H}_3 \mathrm{O}^{+}$forms a compound (Z). 0.1 mole of (Z) will weigh $\_\_\_\_$ g. (Nearest integer)

Identify the structure of the final product (D) in the following sequence of the reactions :

Total number of $\mathrm{sp}^2$ hybridised carbon atoms in product D is ____________.

A compound ' $\mathrm{X}^{\prime}$ absorbs 2 moles of hydrogen and ' X ' upon oxidation with $\mathrm{KMnO}_4 \mid \mathrm{H}^{+}$ gives

The total number of $\sigma$ bonds present in the compound ' $X^{\prime}$ ' is __________.