Milk of magnesia is

The equation of the tangent to the curve $y = b e^{-x/a}$ at the point where it crosses the $y$-axis is:

Four successive members of the first series of the transition metals are listed below. For which one of them the standard electrode potential $(E^o_{M^{2+}/M})$ value has a positive sign?

The reaction $X \rightarrow \text{products}$ is a first order reaction. In $40 \text{ minutes}$,the concentration of $X$ changes from $1.0 \text{ M}$ to $0.25 \text{ M}$. What is the rate of reaction when $[X] = 0.1 \text{ M}$? $(\log 4 = 0.60)$

At $T(K)$,$100 \ L$ of dry oxygen is present in a sealed container. It is subjected to silent electric discharge,till the volumes of oxygen and ozone become equal. What is the volume (in litres) of ozone formed at $T(K)$?

The focal distance of a point on the parabola $y^2 = 16x$ whose ordinate is twice the abscissa,is