Which of the following compounds is not chiral?

The locus of the centre of the circle,which cuts the circle $x^2+y^2-20x+4=0$ orthogonally and touches the line $x=2$,is

The dispersive powers of the materials of two lenses forming an achromatic combination are in the ratio of $4: 3$. If the effective focal length of the two lenses is $+60 ~cm$,then the focal lengths of the lenses should be:

The function $f: R \rightarrow R$ is defined by $f(x) = \cos^2 x + \sin^4 x$ for $x \in R$. Then the range $f(R)$ is equal to

Each of the roots of the equation $x^3-6x^2+6x-5=0$ is increased by $h$. If the new transformed equation does not contain the $x^2$ term,then $h$ is equal to:

Maximum bond angle is present in