The compound formed on heating chlorobenzene with chloral in the presence of concentrated sulphuric acid is:

The equation of the normal to the curve $y^4=ax^3$ at $(a, a)$ is

The chemical entities present in the thermosphere of the atmosphere are:

An inductor of inductance $L=400\,mH$ and resistors of resistance $R_1=2\,\Omega$ and $R_2=2\,\Omega$ are connected to a battery of emf $E=12\,V$ as shown in the figure. The internal resistance of the battery is negligible. The switch $S$ is closed at $t=0$. The potential drop across $L$ as a function of time is

If the extremities of a diagonal of a square are $(1, -2, 3)$ and $(2, -3, 5)$,then the length of its side is

The number of solutions of the system of equations $2x + y - z = 7$,$x - 3y + 2z = 1$,and $x + 4y - 3z = 5$ is