Which of the following metals will react with water?

The ratio of thermal conductivity of two rods of different materials is $5 : 4$. If the two rods have the same cross-sectional area and the same thermal resistance,what is the ratio of their lengths?

Thermite is a mixture of

If for some reason the parietal cells of the gut epithelium become partially non-functional,what is likely to happen?

$\mathop {\lim }\limits_{x \to 0} \frac{{x\tan 2x - 2x\tan x}}{{{{(1 - \cos 2x)}^2}}}$ is

In the following sequence of reactions,what is $D$?
$Toluene$ $\xrightarrow{[O]} A$ $\xrightarrow{SOCl_2} B$ $\xrightarrow{NaN_3} C$ $\xrightarrow{\text{Heat}} D$