4no + 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.