Which of the following orbitals has zero probability of finding the electron in the $YZ$ plane?

The standard entropies of $X_2$,$Y_2$,and $XY_3$ are $60$,$40$,and $50 \ J \ K^{-1} \ mol^{-1}$ respectively. For the reaction $\frac{1}{2}X_2 + \frac{3}{2}Y_2 \to XY_3$,$\Delta H = -30 \ kJ$. What will be the temperature in $K$ at equilibrium?

The number of atoms in $100 \ g$ of an $fcc$ crystal with density $d = 10 \ g/cm^3$ and cell edge length $a = 100 \ pm$ is:

The solubility of $N_2$ in water at $300 \ K$ and $500 \ torr$ partial pressure is $0.01 \ g \ L^{-1}$. The solubility (in $g \ L^{-1}$) at $750 \ torr$ partial pressure is

Identify the strongest base from the given compounds:

Synapsis occurs between