When compound $X$ is oxidised by acidified potassium dichromate,compound $Y$ is formed. Compound $Y$ on reduction with $LiAlH_4$ gives $X$. $X$ and $Y$ respectively are :

The synonym for water gas when used in the production of methanol is

The $IUPAC$ name for the complex $[Co(NO_2)(NH_3)_5]Cl_2$ is:

$A$ thermodynamic system undergoes a cyclic process $ABCDA$ as shown in the figure. The work done by the system in the cycle is

The molecular formula of diphenylmethane is $C_{13}H_{12}$. How many structural isomers are possible when one hydrogen atom is replaced by a chlorine atom?

An electric dipole is placed along the $x$-axis at the origin $O$. $A$ point $P$ is at a distance of $20 \ cm$ from this origin such that $OP$ makes an angle $\frac{\pi}{3}$ with the $x$-axis. If the electric field at $P$ makes an angle $\theta$ with the $x$-axis,the value of $\theta$ would be