1). ) Law of conservation of mass : (Lavoisier and Landolt) . Matter is neither created nor destroyed in the course of chemical reaction though it may change from one form to other . The total mass of materials after a chemical reaction is same as the total mass before reaction. (2) Law of constant or definite proportion : Proust A pure chemical compound always contains the same elements combined together in the fixed ratio of their weights whatever its methods of preparation may be. (3) Law of multiple proportion : Dalton and Berzelius When two elements A and B combine to form more than one chemical compounds then different weights of A, which combine with a fixed weight of B, are in proportion of simple whole numbers. (4) Law of equivalent proportion or law of reciprocal proportion : Ritcher The weights of the two or more elements which separately react with same weight of a third element are also the weights of t
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Carbohydrates MCQ
Sucrose on hydrolysis gives (a) Two molecules of glulcose (b) Two molecules of fructose (c) One molecule each of glucose and fructose (d) One molecule each of glucose and mannose Which of the following is a disaccharide (a) Lactose (b) Starch (c) Cellulose (d) Glucose Glucose cannot be classified as (a) A hexose (b)A carbohydrate (c) An oligosaccharide (d)An aldose The reagent which forms crystalline osazone derivative when reacted with glucose, is (a) Fehling solution (b) Phenylhydrazine (c) Benedict solution (d) Hydroxylamine An enzyme which brings about the conversion of starch into maltose is known as (a) Maltase (b) Zymase (c) Invertase (d) Diastase Canesugar on hydrolysis gives (a) Glucose and maltose (b) Glucose and lactose (c) Glucose and fructose (d) Only glucose Glucose is a (a) Monosaccharide (b) Disaccharide (c) Trisaccharide (d) Po
Gattermann-koch aldehyde synthesis
Gattermann-koch aldehyde synthesis : Benzene(C6H6) is converted into benzaldehyde by passing a mixture of carbon monoxide(CO) and HYDROCHLORIC ACID (HCl) gas under high pressure into the ether solution of benzene in presence of anhydrous aluminium chloride (AlCl3)and cuprous chloride CuCl2.
Stephen Aldehyde Synthesis
Stephen Aldehyde Synthesis When we convert cyanides into aldehydes by a method of partial reduction in presence of SnCl 2 /HCl, which is followed by hydrolysis , is called as Stephens aldehyde synthesis Stephen aldehyde synthesis was first used by Henry Stephen . This reaction used for preparation of aldehydes (R-CHO) from nitriles (R-CN) using tinchloride (SnCl 2 ) and hydrochloric acid (HCl). This reaction is more useful when aromatic nitriles are used but not for all aromatic nitriles.