The rate of the reaction of nitrogen monoxide with oxygen was measured at 25 degrees C. starting with various initial concentrations of reactants NO and O2. 2NO(g) + O2(g)---> 2NO2(g) initial concentrations reaction rate mol/L mol/l. s NO(g) O2(g) Trial #1 .020 .010 .028 Trial #2 .020 .020 .057 Trial #3 .040 .020 .227 A) Use the method of initial rates to find the reaction orders with respect to NO and O2. Hint: for which trials was the concentration of NO changed while [O2] remained constant?

the answer is option a.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2