Concentration of solution refers to the amount of solute dissolved in a unit volume of solution. Mole Concept and Stoichiometry Main Note


As concentration increases the number of reacting particles per unit volume also increases. Collide more frequently frequency of effective collisions increases.


Sample

Rate of Reaction increases with an increase in concentration:

  • there are more reacting particles per unit volume, the particles are closer together
  • resulting in more collisions between the reacting particles per unit time.
  • thus frequency of effective collisions increases
  • hence rate of reaction increases.

Sample

Rate of Reaction decreases with decrease in concentration

  • there are fewer reacting particles per unit volume, the particles are further apart from each other
  • resulting in fewer collisions between the reacting particles per unit time.
  • thus frequency of effective collisions decreases
  • hence speed of reaction decreases

Real Sample: Explain why higher concentration of acid affects rate of reaction between acid and magnesium ribbon

  • at higher concentration, there are more reacting particles of acid per unit volume, particles are closer together
  • this results in more collision between reacting particles (of acid and Mg or H+ ions and Mg atoms) per unit time
  • thus frequency of effective collisions increases and the rate of reaction also increases


Summary

increase in concentration of reactants increases rate of reaction

i didn’t add it but try to add per unit time in these answers as it makes it more accurate and greater chance of getting it correct.