Find the number of following molecules having greater extent of hydrolysis as compared to ${\mathrm{CCl}}_4$. 

${\mathrm{MgCl}}_2,{\mathrm{AlCl}}_3,{\mathrm{PCl}}_5,{\mathrm{SiCl}}_4$

By increasing the chlorine atom, the charges on the central atom of the molecule increases which lead to increase the attack of nucleophile. So, correct increasing order of extent of hydrolysis is 

${\mathrm{CCl}}_4<{\mathrm{MgCl}}_2<{\mathrm{AlCl}}_3<{\mathrm{SiCl}}_4<{\mathrm{PCl}}_5$.