Batrachospermum Occurrence:- (1) Batrachospermum is fresh water alga. (2) It is found in clear, cool, and running streams. (3) Deepwater plants are dark violet or reddish in color. But the shallow-water species are olive green. (4) The intensity of light changes the color of pigments. (5) The thallus is attached to the substratum. Vegetative structure (1) The thallus of an adult plant is soft, thick, filamentous. (2) It is freely branched and gelatinous. (3) The central axis is made up of a single row of large cells. Whorls of branches of limited growth are developed on this axis. (4) These branches are filamentous and dichotomously arranged. (5) The main axis is corticated. It consists of a row of elongated cylindrical cells. (6) It is differentiated into nodes and internodes. (7) There are two types of branches that arise from the nodes: Branches of limited growth Branches of unlimited growth Batra
Haloalkanes &Haloarenes Haloalkanes and Haloarenes may be classified as follow : On the basis number of halogen atoms:- Monohaloalkanes further classified according to the hybridization of the carbon atom to which the halogen is bonded. ( a)Compound containing Sp3 C---X Bond. Mono and Dihaloalkanes Alkyl Halide or Haloarenes: Allylic halide : Halogen attaches to the Sp2 carbon next to the Sp2 hybridized carbon. Benzylic halide : These are the compounds in which the halogen atom is bonded to an Sp3 hybridized carbon next to the aromatic ring. Vinyl halide : Halogen atom is bonded to Sp2 hybridized carbon atom of a carbon-carbon double bond (C=C). Aryl halide : Compounds in which halogen is bounded by Sp2 carbon the aromatic ring. Nature of C---X bond: Halogen is more electronegative than carbon, the carbon halide bond of alkyl halide is polarized, carbon bears partially positive charge and halide bears a negative cha