Chlorine gas can be prepared in the laboratory by the reaction of hydrochloric acid with manganese(iv) oxide: you add 40.7 g of mno2 to a solution containing 42.7 g of hcl.(a) what is the limiting reactant? (b) what is the theoretical yield of cl2? (c) if the yield of the reaction is 81.5%, what is the actual yield of chlorine?

:  4 HCl + MnO2 → MnCl2 + 2 H2O + Cl2 

(33.7 g MnO2) / (86.93691 g MnO2/mol) = 0.38764 mol MnO2 
(45.3 g HCl) / (36.4611 g HCl/mol) = 1.2424 mol HCl 

(a) 
1.2424 moles of HCl would react completely with 1.2424 x (1/4) = 0.3106 mole of MnO2, but there is more MnO2 present than that, so MnO2 is in excess and HCl is the limiting reactant. 

(b) 
(1.2424 mol HCl) x (1 mol Cl2 / 4 mol HCl) x (70.9064 g Cl2/mol) = 22.0 g Cl2 

(c) 
(77.7% of 22.0 g Cl2) = 17.1 g Cl2

m=9

step-by-step explanation:

7m+8=71 subtract   8 from 71 which is 63 than divide it by 7m   equal 9.