4 NO + O2 + 2 H2O → 4 HNO2 The reaction above is second order in nitric oxide and first order in oxygen. How much faster will the rate be if the concentration of NO is tripled? 9 times faster 6 times faster 3 times faster 8 times faster

Increases rate of rxn 9X

Explanation:

Given 4NO + O₂ + 2H₂O = > 4HNO₂

Rate = k[NO]²[O₂]; if [O₂] is kept constant = > Rate = k[NO]²

For 2nd order reactions Rate = k[A]². If [A] = a, 2a, 3a ... then the Rate trend for a 2nd order reaction is ...

Rate 1 = k (a) ² = ka²

Rate 2 = k (2a) ² = 4ka²

Rate 3 = k (3a) ² = 9ka² < = 3X increase in concentration

Rate 4 = k (4a) ² = 16ka²

Increasing the concentration of NO by 3 times while keeping concentrations of O₂ and H₂O constant increases rate of reaction by 9 times.