Which one of the following is mainly responsible for the depletion of the ozone layer?

In which of the following reactions will cyanide be obtained as a major product?

Heat energy is incident on the surface at the rate of $1000 ~J/min$. If the coefficient of absorption is $0.8$ and the coefficient of reflection is $0.1$,then the heat energy transmitted by the surface in $5 ~min$ is: (in $~J$)

If $x^3 + y^3 - 3axy = 0$,then $\frac{dy}{dx}$ equals

In which of the following reactions,$H_2O_2$ acts as a reducing reagent?

As the mass number $A$ increases,which of the following quantities related to the nucleus does not change?