The number of $\alpha$ and $\beta$-particles emitted during the transformation of $_{90}Th^{232}$ to $_{82}Pb^{208}$ are respectively

Which one of the following nuclear reactions is correct?

An artificial radioactive isotope gave $_7^{14}N$ after two successive $\beta$-particle emissions. The number of neutrons in the parent nucleus must be

Which isotope on bombardment with $\alpha$-particles will give $_8O^{17}$ and $_1H^1$?

$_{13}Al^{28}$ when radiated by a suitable projectile gives $_{15}P^{31}$ and a neutron. The projectile used is:

$A$ closed vessel with rigid walls contains $1 \ mol$ of ${ }_{92}^{238} U$ and $1 \ mol$ of air at $298 \ K$. Considering the complete decay of ${ }_{92}^{238} U$ to ${ }_{82}^{206} Pb$, the ratio of the final pressure to the initial pressure of the system at $298 \ K$ is: