What is the major product of the following reaction?

$A$ liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
$a$. What is the initial effect of the change on vapour pressure?
$b$. How do rates of evaporation and condensation change initially?
$c$. What happens when equilibrium is restored finally and what will be the final vapour pressure?

If $x_1$ and $x_2$ are the real roots of the equation $x^2-kx+c=0$,then the distance between the points $A(x_1, 0)$ and $B(x_2, 0)$ is

The major product in the following reaction is:

If $\lambda_0$ is the de-Broglie wavelength for a proton accelerated through a potential difference of $100 \ V$,the de-Broglie wavelength for an $\alpha$-particle accelerated through the same potential difference is

In the nuclear reaction,${ }_{90}^{234} Th \longrightarrow{ }_{91}^{234} Pa + X$,$X$ is: