Calculate the amount of heat (in calories) required to convert $5\,g$ of ice at $0\,^{\circ}C$ to steam at $100\,^{\circ}C$.

If the electron of a hydrogen atom is present in the first orbit,the total energy of the electron is

The correct order of increasing $s-$character (in percentage) in the hybrid orbitals of the following molecules/ions is:
$(I)$ $CO_3^{2-}$ $(II)$ $XeF_4$ $(III)$ $I_3^-$ $(IV)$ $NCl_3$ $(V)$ $BeCl_2$

In which of the following pairs,the central atoms have the same number of lone pairs of electrons?

If you suspect a major deficiency of antibodies in a person,to which of the following would you look for confirmatory evidence?

An inclined plane makes an angle of $30^{\circ}$ with the horizontal. $A$ solid sphere rolling down this inclined plane from rest without slipping has a linear acceleration equal to ........