Among the given cations,the most stable carbonium ion is?

The maximum value of $\frac{\log x}{x}, 0 < x < \infty$ is

In which of the following processes is $CO_2$ not produced?

In an elastic collision of two particles,which of the following quantities is conserved?

If the points with position vectors $60 \hat{i}+3 \hat{j}$, $40 \hat{i}-8 \hat{j}$, and $a \hat{i}-52 \hat{j}$ are collinear, then $a$ is equal to

Which one of the following elements reacts with steam?