The question is incomplete, here is the complete question:
Carbon tetrachloride reacts at high temperatures with oxygen to produce two toxic gases, phosgene and chlorine.
at 1,000 K
Calculate Kc for the reaction 
<u>Answer:</u> The value of
for the final reaction is 
<u>Explanation:</u>
The given chemical equations follows:

We need to calculate the equilibrium constant for the equation, which is:

As, the final reaction is the twice of the initial equation. So, the equilibrium constant for the final reaction will be the square of the initial equilibrium constant.
The value of equilibrium constant for net reaction is:

We are given:

Putting values in above equation, we get:

Hence, the value of
for the final reaction is 
Explanation:
In a double displacement reaction, there is an actual exchange of partners to form new compounds.
The reaction is given as shown below:
AB + CD → AD + CB
One of the following conditions serves as the driving force for a double replacement reaction:
- Formation of an insoluble compound or precipitate
- Formation of water or any other non-ionizing compound
- Liberation of a gaseous product.
Answer;
-Chlorine is more reactive than silicon
Explanation;
-As you move across a period, the nuclear charge will increase; the number of energy levels will stay the same, so there is a stronger and stronger attraction for the electrons.
-The electrons are being held more tightly as you move across a period. It becomes more and more difficult to lose electrons and consequently the reactivity of non metals increases as you go from left to right across the periodic table; Therefore; chlorine is more reactive than silicon.