Saponification is

Sodium metal crystallizes in a body-centred cubic $(bcc)$ lattice with a unit cell edge of $4.29 \ \mathring{A}$. The radius of the sodium atom is approximately: .............. $\mathring{A}$

In which of the following processes does entropy decrease?

If the gravitational acceleration at the surface of the Earth is $g$,then the increase in potential energy in lifting an object of mass $m$ to a height equal to half of the radius of the Earth from the surface will be

$A$ gamma ray photon creates an electron-positron pair. If the rest mass energy of an electron is $0.5 \, MeV$ and the total $K.E.$ of the electron-positron pair is $0.78 \, MeV$,then the energy of the gamma ray photon must be .......... $MeV$.

Which of the following amines undergoes acylation reaction?