Chemical Kinetics – Solutions

1) From the rate expression for the following reactions, determine their order of reaction and the dimensions of the rate constants.

i) 3NO (g) ®N₂O (g) Rate = k[NO]²

ii) H₂O₂(aq) + 3I^–(aq) + 2H⁺ ®H₂O(l) + I₃^– Rate= k [H ₂O₂][I^–]

iii) CH₃CHO (g) ® CH₄(g) + CO(g)                Rate= k[CH₃CHO]^3/2

iv) C₂H₅Cl(g) ® C ₂H₄(g) +HCl(g) Rate= k [C₂H₅Cl]

Solution

The sum of the powers to which the concentration of reacting species are raised in rate law expression is called the order of reaction.

Dimension of rate constant of  a reaction is given as