Classify the following as amorphous or crystalline solids: polyurethane, naphthalene, benzoic, acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

Classify the following into crystalline and amorphous solids. NaCl ,Graphite , Plastic, Diamond, Rubber, KCI, Wood, CaC0_3 , Iodine .

How do you account for the following observations? a) Though alkaline potassium permanganate and acidic potassium permanganate both are used as oxidants, yet in the manufacture of benzoic acid from toluene we use alcoholic potassium permanganate as an oxidant. Why? Write a balanced redox equation for the reaction. b) When concentrated- sulphuric acid is added to an inorganic mixture containing chloride, we get colourless pungent smelling gas 'HCl', but if the mixture contains bromide, then we get red vapours of bromine. Why?

Based on the nature of order, present in the arrangement of the constituent particles, solids are classified into two, crystalline and amorphous. List out any four points of difference between crystalline end amorphous solids. b) Alist of solids are given below : Quartz, glass, iodine, ice. From this, identify crystal (s) i) having sharp melting point. ii) which is/are isotropic