Answer:
K=1.93
Explanation:
Given reactions are:
A +2B ⇄ 2C K1=2.79
2C ⇄ D K2=0.186
D⇄ A+ 2B K=?
If we reverse the reaction then the euillibrium constant also become reciprocal of original value:
3rd reaction is a combination of reciprocal of 1st and 2nd reaction
2C⇄A +2B 1/K1;........................1
D ⇄ 2C 1/K2; ..............................2
On adding 1 and 2
D ⇄A +2B 

K=1.93
Answer: Its C: Trigonal Planar
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Answer:
Answer in explanation
Explanation:
a. Boron , element 5
Helium has 2 electrons, add to the other 3 to give 5.
Other group members are : Aluminum Al, Gallium Ga, Indium In , Thallium Tl and Nihonium Nh
b. Sulphur, element 16
Neon is 10 , add other 6 electrons to make 16
Other group members are: Oxygen O, selenium Se , Tellurium Te and Polonium Po
c. Lanthanum, element 57
Xenon is 54, add the other 3 electrons to give 57.
Other elements in group : Scandium Sc , Yttrium Y , Actinium Ac, Lutetium Lu and/or Lawrencium Lr