Questions 2 and 4 on this question.

2) Cl2+H2O=H+ +Cl- +HCl, in the equilibrium constant, the concentration of solvent solids is calculated as 1, because it is generally a constant, so it is included in the equilibrium constant.

k=4) The solubility increases due to the increase of chlorine pressure.

The equilibrium will shift to the right, that is, the reaction of Cl2 and H2O will occur, and the Cl-, H+, and HCl concentrations will gradually increase, and the Cl2 concentrations will gradually decrease, and the equilibrium will be reached when it is known that their concentration ratio is equal to the equilibrium constant.

Cl2+H2O= H+ +Cl- +HClO starting concentration 0 0 0

Transformation concentration. Equilibrate concentration.

k=c(h+)c(cl-)c(hclo)/c(cl2)==4) cl2=cl2（aq)

When the pressure increases, the solubility of Cl2 in water increases, the concentration of Cl2 increases, and the equilibrium shifts to the right.

I still have to ask the first question first.

Set up each round to infect x people.

Well, there is:

1+x+（1+x）x=49

1+x+x+x2=49

x2+2x-48=0

x+8）（x-6）=0

x=-8 (undesirable).

x=6 after the third round.

49x6=294 (person).

After the fourth round, it is.

294x6 = 1764 (people).

A: Since the fourth round, 1,764 people have been infected.

The rule of this problem is: 7+(n-1) 3, where n is the number of small trapezoids.

So when the number of small trapezoids is 10, its circumference is 7 + (10-1) 3 = 3 and the number is 34

When the number of small trapezoids is 11, its circumference is 7+(11-1)3 37

135…(2n-1) (2n)…642——— from front to back: 3 and the following 2 form a reverse order, there is 1; 5 and the following 42 form a reverse order, there are 2; …2n-1) and the following (2n-2)....642 are all in reverse order, there are n-1; In addition, (2n) and (2n-2)....642 are all in reverse order, there are n-1; (2n-2) and (2n-4)....642 all constitute reverse order, there are n-2; ..., 4 and the following 2 form a reverse order, there is 1; So the inverse ordinal number is 1+2+....+n-1)+(n-1)+…2+1=n(n-1)。