The least positive integer $n$ for which $(1+i)^n=(1-i)^n$ is

The angle between the straight lines $x^2+4xy+y^2=0$ is....... (in $^{\circ}$)

In $Fe(CO)_5$,the $Fe-C$ bond possesses

The molecular formula of compound $A$ is $C_2Cl_3OH$. It reduces Fehling's solution and on oxidation gives a monocarboxylic acid $B$. Compound $A$ is obtained by the reaction of chlorine with ethyl alcohol. What is $A$?

The Cartesian form of the polar equation $\theta = \tan^{-1} 2$ is

The compressibility factor for an ideal gas is