Identify A in the given chemical reaction. CH$_2$=CH-CH(CH$_3$)-CH$_3$ $\xrightarrow{Mo_2O_3, 773 K, 10-20 atm}$ A (major product) 

Consider the following reaction sequence.
Which of the following hydrocarbons reacts easily with MeMgBr to give methane? 

In the following \(p\text{–}V\) diagram, the equation of state along the curved path is given by \[ (V-2)^2 = 4ap, \] where \(a\) is a constant. The total work done in the closed path is: 