Which of the following is monoatomic?

The electric field component of an electromagnetic wave in vacuum is given as $\vec E = 3\cos(1.8y + 5.4 \times 10^8 t)\hat i$. Its direction of propagation and wavelength are:

Which of the following will release hydrogen gas upon reaction with hydrochloric acid?

The metal used for the de-bromination reaction of $1, 2-dibromoethane$ is:

$100 \ mL$ of $0.6 \ M$ acetic acid is shaken with $2 \ g$ of activated charcoal. After adsorption,the final concentration of the solution becomes $0.5 \ M$. The amount of acetic acid adsorbed per gram of carbon is .......... $g$.

The radius of the circle $r = \sqrt{3} \sin \theta + \cos \theta$ is