Acetone on addition to methyl magnesium bromide forms a complex,which on decomposition with acid gives $X$ and $Mg(OH)Br$. Which one of the following is $X$?

The mass of a planet is half that of the earth and the radius of the planet is one-fourth that of earth. If we plan to send an artificial satellite from the planet,the escape velocity will be,(escape velocity on earth $v_e = 11 \ km \ s^{-1}$) (in $km \ s^{-1}$)

Which type of chromosome is shown in the figure below?

$A$ tube of length $L$ is filled completely with an incompressible liquid of mass $M$ and closed at both ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity $\omega$. The force exerted by the liquid at the other end is

If the freezing point of an aqueous solution of salt $MX_4$ $(\alpha = 90\%)$ is $-3\,^{\circ}C$,then its boiling point will be ......... $^{\circ}C$. (Assume it is $100\%$ ionized at boiling temperature and $k_f = 1.86\,K\,kg\,mol^{-1}, k_b = 0.52\,K\,kg\,mol^{-1}$)

When a light of a given wavelength falls on a metallic surface the stopping potential for photoelectrons is $3.2 \ V$. If a second light having wavelength twice of first light is used, the stopping potential drops to $0.7 \ V$. The wavelength of first light is . . . . . . $m$.
$(h = 6.63 \times 10^{-34} \ J.s, e = 1.6 \times 10^{-19} \ C, c = 3 \times 10^8 \ m/s)$