Consider the rate law below. r=k(no2)^2 what happens to the rate if the concentration is tripled? the rate increases by a factor of 9. the rate decreases by a factor of 6. the rate triples. the rate doubles.

For this case we have the following equation:
 R = k (NO2) ^ 2
 if the concentration is tripled, we must rewrite the equation.
 We have then:
 R '= k (3 * NO2) ^ 2
 R '= 9 * k (NO2) ^ 2
 Rewriting:
 R '= 9 * R
 
 The rate increases by a factor of 9.

Answer might be d.i think