The $P-P-P$ bond angle in white phosphorus is

Identify phenacetin from the following.

Two particles $A$ and $B$ of equal masses are suspended from two massless springs of spring constants $k_1$ and $k_2,$ respectively. If the maximum velocities during oscillations are equal,the ratio of amplitudes of $A$ and $B$ is

Which among the following is a pair of monocarboxylic acids?

The diameters of a circle are along $2x+y-7=0$ and $x+3y-11=0$. Then,the equation of this circle,which also passes through $(5,7)$,is

What is the chemical nature of alane?