The catalyst used for the polymerization of olefins is....

Assertion $(A)$: $K, Rb$ and $Cs$ form superoxides.
Reason $(R)$: The stability of the superoxides increases from $K$ to $Cs$ due to decrease in lattice energy.
The correct answer is

An electrically charged particle enters a uniform magnetic field in a direction perpendicular to the field with a velocity $v$. Then,it travels

An ideal gas is taken through the cycle $A \to B \to C \to A$,as shown in the figure. If the net heat supplied to the gas in the cycle is $5 \ J$,the work done by the gas in the process $C \to A$ is .... $J$.

The first operation involved in a Carnot cycle is

The temperature in $K$ at which $\Delta G = 0$ for a given reaction with $\Delta H = -20.5 \ kJ \ mol^{-1}$ and $\Delta S = -50.0 \ J \ K^{-1} \ mol^{-1}$ is: