## Different methods for calculating the value of Rate Constants Chemistry Notes

**Different Methods for Calculating the value of Rate Constant :**

Volumetric Method : This method is suitable for that reaction in which reactant or product is either acid or base or these represent redox reactions. Following formulae are given for the determination of order of these reactions :

→ Optical Rotation Method : In this method, order of those reactions is determined which represent polarity rotation and reactant or product either represent laevo rotation or dextro rotation ie, either reactant or product is optically active. By this method, order of reaction can be calculated by the formula:

Here, r_{0} = Angle of rotation in initial state of reaction

r_{t} = Angle of rotation at time intervalt

r_{∞} = Angle of rotation at infinite time

Pressure Change Method : This method is used in that condition when reactant and product both exist in gaseous state.

Here, x mole reactant is converted into product and form x mole Band x mole C.

Determination of Order with the help of Half-life Let, consider the two initial concentrations for a reactant which are [A_{1}] and [A_{2}] respectively for (t_{1/2})_{1} and (t_{1/2})_{2}. Their order can be determined as follows