Which one of the following reactions is an example of oxidative decarboxylation?

Which one of the following is correct?

Which substance is used as a smoke screen in warfare?

Two waves $Y_{1} = 0.25 \sin(316 t)$ and $Y_{2} = 0.25 \sin(310 t)$ are propagating along the same direction. The number of beats produced per second is:

$CaCl_2$ and $Ca(OCl)_2$ are components of:

Water is drained from a vertical cylindrical tank by opening a valve at the base of the tank. It is known that the rate at which the water level drops is proportional to the square root of water depth $y$,where the constant of proportionality $k > 0$ depends on the acceleration due to gravity and the geometry of the hole. If $t$ is measured in minutes and $k = \frac{1}{15}$,then the time to drain the tank if the water is $4 \text{ m}$ deep to start with is ......... $\text{min}$.