The idea of producing by-product hydrochloric acid with chlorine instead of methane has become a reality in industry. A chemistry interest group simulated it in the laboratory.

(1) Under heating conditions, manganese dioxide reacts with concentrated hydrochloric acid to generate chlorine gas, which also contains water. Concentrated sulfuric acid has water absorption, dehydration and strong oxidation, so device B not only controls the air flow rate, but also has the function of drying, so the answer is: drying the mixed gas;

(2) Chlorine reacts with methane. The characteristic of the reaction is that 1mol chlorine can replace 1mol atomic generation 1mol HCl. Let V(Cl2)/V(CH4)=x, in theory, to get the most hydrogen chloride, it is necessary to ensure that methane is completely replaced, and X should be greater than or equal to 4, so the answer is: 4;

(3) Chlorine gas has a strong oxidizing property, which can oxidize iodine ions into elemental iodine, so KI powder is evenly mixed in the asbestos in device D, and its function is to absorb excessive chlorine gas, so the answer is: absorb excessive chlorine gas;

(4) The generated small black particles are carbon black, and CH4+2Cl2 illumination C+4HCl can occur under strong light irradiation, so the answer is: CH4+2Cl2 illumination C+4hcl;

(5) Hydrochloric acid and organic matter are immiscible with each other and can be separated by liquid separation, so A is selected;

(6) Let the mass of sodium hydroxide be x,

The equation of electrolytic saturated salt solution is: 2NaCl+2H2O=Cl2↑+H2↑+2NaOH.

22.4L？ 80 grams

1 1.2× 106L x

22.4 l: 80 g = 1 1.2× 106 l: x.

X = 80g×11.2x106l22.4l = 4x107g = 40 tons,

So the answer is: 40.