Which of the following is a symbiotic nitrogen fixer?

$A$ satellite is revolving very close to a planet of density $\rho$. The period of revolution of the satellite is

Assertion : For an isothermal reversible process $Q = -W$,i.e.,work done by the system equals the heat absorbed by the system.
Reason : Enthalpy change $(\Delta H)$ is zero for an isothermal process.

If $y=\frac{\log _e x}{x}$ and $z=\log _e x$,then $\frac{d^2 y}{d z^2}+\frac{d y}{d z}$ is equal to

Which one of the following reactions occurs at the anode in the Castner process of extracting sodium metal?

Which of the following reactions defines $\Delta H_f^o$?