Extraction of zinc from zinc blende is achieved by:

If the rate of disappearance of $N_2O_5$ in the following reaction is $1.2 \times 10^{-5} \ mol \ L^{-1} \ s^{-1}$,the rate of production of $NO_2$ in $mol \ L^{-1} \ s^{-1}$ is:
$2 \ N_2O_{5(g)} \longrightarrow 4 \ NO_{2(g)} + O_{2(g)}$

In which of the following reactions,chlorine acts as an oxidising agent?
$(i)$ $CH_3CH_2OH + Cl_2 \longrightarrow CH_3CHO + HCl$
$(ii)$ $CH_3CHO + Cl_2 \longrightarrow CCl_3CHO + HCl$
$(iii)$ $CH_4 + Cl_2 \xrightarrow{hv} CH_3Cl + HCl$
The correct answer is

If $n$ is an integer with $0 \leq n \leq 11$,then the minimum value of $n!(11-n)!$ is attained when a value of $n$ equals to

If $5 \cos x + 12 \cos y = 13$,then the maximum value of $5 \sin x + 12 \sin y$ is:

Power supplied to a particle of mass $2\, kg$ varies with time as $P = \frac{3t^2}{2} \, W$. Here $t$ is in $seconds$. If the velocity of the particle at $t = 0$ is $v = 0$,the velocity of the particle at time $t = 2\, s$ will be ........... $m/s$.