By Sunil Bhardwaj

3459 Views

A reaction is said to be of the first order if the rate of the reaction depends upon one concentration term only. E.g. $$N_2O_2(g) \longrightarrow N_2O_4(g) + \frac12{ O }_{ 2 }(g) \text{ (First Order reaction) }$$

Equation for rate constant for first order reaction is $$\boxed { k = \frac { 2.303 }{ t } \log { \frac { a }{ a-x } } }$$ $$\therefore \frac { kt }{ 2.303 } = \log { \frac { a }{ a-x } }$$ or $$\frac { kt }{ 2.303 } = \log { \left( a \right) } - \log { \left( a-x \right) }$$ $$\therefore \boxed { \log { \left( a-x \right) } = -\frac { kt }{ 2.303 } + \log { \left( a \right) } }$$ which is similar to straight line graph, $$\boxed { y = mx + c }$$ where slope $$\boxed { m = -\frac { k }{ 2.303 } }$$ and intercept $$\boxed { c = \log { \left( a \right) } }$$ Thus from the plot of $$\log { \left( a-x \right) }$$ Vs $$t$$ we can calculate the value of rate constant k, as $$\boxed { k = 2.303 \times \left( -slope \right) }$$ -ve sign indicates that the concentration of reactants decreases with time.

#### Latest News

• Become an Instructor 4 March, 2018

Apply to join the passionate instructors who share their expertise and knowledge with the world. You'll collaborate with some of the industry's best producers, directors, and editors so that your content is presented in the best possible light..

#### More Chapters

• Spectroscopy
• Basic Quantum Chemistry
• Phase Rule
• Electrochemistry
• Colloidal State
• Chemical Thermodynamics
• Gaseous State
• Applied Electrochemistry
• Ionic Equilibria
• Nuclear Chemistry
• Solid State Chemistry
• Chemical Kinetics
• #### Other Subjects

• English
• Applied Physics
• Environmental Studies
• Physical Chemistry
• Analytical Chemistry
• Organic Chemistry
• Soft Skills
• Engineering Drawing
• General Medicine
• Mathematics
• Patente B Italia