Calculate the frequency of visible light having a wavelength of 486 nm

Ν= c/λ

λ= 486 nm * ( 1 m / 1x10^9 nm) = 4.86 x10^-7 m 

v= (3.00 x 10^8 m/s) /  (4.86 x10^-7 m) 
v= 6.1728395x 10^14 s^-1
= 6.14 x10^-14 Hz

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf   

Hi + naoh -> h2o + nal