is a well known anti-pyretic and analgesic that is prescribed in cases of fever and body pain. Pharmacokinetic studies showed that Paracetamol has a half-life of . hours within the body i.e. the plasma concentration of a drug is halved after .
hrs. After hours ( half-lives)only . % of drug remains. Based on such studies the dosage and frequency will be decided.
In case of paracetamol, it is usually prescribed to take once in hours depending upon the conditions. XII U7 kinetics - Jerald XII U7 kinetics - Jerald - - - - i.e., it does not depend on the initial concentration. According to collision theory, chemical reactions occur as a result of collisions between the reacting molecules. Generally, the rate of a reaction increase with increasing temperature.
However, there are very few exceptions. The magnitude of this increase in rate is different for different reactions. As a rough rule, for many reactions near room temperature, reaction rate tends to double when the temperature is increased by C According to Arrhenius, activation energy of the reaction is the minimum energy that a molecule must have to posses to react. The rate of a reaction is affected by the following factors.
. Nature and state of the reactant . Concentration of the reactant . Surface area of the reactant .
Temperature of the reaction . Presence of a catalyst EVALUATION . For a first order reaction A B the rate constant is x min − . If the initial concentration of A is .01M , the concentration of A after one hour is given by the expression.
a) e − x b) − e x c) − e x d) none of these . A zero order reaction X Product , with an initial concentration .02M has a half life of min. if one starts with concentration .04M, then the half life is a) s b) min c) min d) cannot be predicted using the given information .