What is the correct order of stability for the superoxides?

Steam at $100\,^{\circ}C$ is passed into $1.1\,kg$ of water contained in a calorimeter of water equivalent $0.02\,kg$ at $15\,^{\circ}C$ until the temperature of the calorimeter rises to $80\,^{\circ}C$. The mass of steam condensed in kilograms is:

${ }^{234}Th_{90}$ gets converted to ${ }^{206}Pb_{82}$ through a series of radioactive decay processes. The number of alpha and beta particles lost in this transformation respectively,are

$\int_{-\pi / 2}^{\pi / 2} \sin |x| \, dx$ is equal to

In an unbiased $p-n$ junction,holes diffuse from the $p-$region to $n-$region because

The structural formula of $2$-methyl-$2$-butene is: