[smatik]

some sols like metal-sulphide sols-As2S3(arsenic-sulphide) is a negative sol. This kind of question are directly asked in our School exams and entrance examinations too. There is a method of preferential selection of ions but for that the experiment is given by which the sol is prepared. But the questions we get, we are just given the name of sol and are asked questions about charge on sol.  Can anyone plz help me in identifying the charge on some sol.