GCSE Chemistry Question Analyses Topic: Chemistry - Short Questions
Exam Question:
1) Out of starch and ferric hydroxide sol. which one can easily be coagulated and why?
2) What type of semiconductor is obtained when
(i) Ge is doped with In?
(ii) Se is doped with P?
Answer:
For GCSE Chemistry, you should know:
1) Starch is a lyophilic sol that is quite stable and difficult to coagulate, whereas ferric hydroxide is a lyophobic sol that coagulates readily when a modest quantity of electrolytes is added.
Thus, it is simpler to coagulate ferric hydroxide sol than starch.
2) (i) Due to the tetravalent nature of Germanium (Ge) and the trivalent nature of Indium (In), p-type semiconductors are produced when Ge is doped with In.
(ii) As phosphorous (P) is pentavalent and selenium (Se) is tetravalent, an n-type semiconductor results when Se is doped with P.
Work hard for your GCSE Chemistry examination!
End of analysis. Great!