Colour of any object is by the colour of light it reflects i.e if white light is incident on the object,it will reflect blue color.so it will appear blue.But if red light is incident on it,it will not reflect that and absorb it.so as it will not reflect any light it will appear black.
Hydrogen ions contains +1 charge while sulphate ions have 2 charge. ... No .of ions in one formula unit of MgC12 =3 Total no of ions in MgC12 =1.20x1024 x3=3.6x1024 ions.
The solution and complete explanation for the above question and mentioned conditions is given below in the attached document.i hope my explanation will help you in understanding this particular question.
