Which one of the following is a true peroxide?

$A$ solution of sodium sulphate contains $92 \ g$ of $Na^{+}$ ions per kilogram of water. The molality of $Na^{+}$ ions in that solution in $mol \ kg^{-1}$ is:

$A$ bar of cross-sectional area $A$ is subjected to two equal and opposite tensile forces at its ends as shown in the figure. Consider a plane $BB'$ making an angle $\theta$ with the length. The ratio of tensile stress to the shearing stress on the plane $BB'$ is

What is obtained by the decomposition of sodium nitrate at a temperature above $800\,^oC$?

The temperature of the system decreases in the process of

Which herbicide is derived from urea and is used for weed control in tea, cotton, and tobacco crops?