Someone plz ans this question
Q.20. (i) Why do fire flies glow at night?
(ii) Write chemical reaction for soda acid fire extinguisher. How does it work?
                                                                      OR
An alkane has molecular mass 86. Find out its molecular formula. Write down all possible isomers for this molecular formula.
 

Dear student,

Kindly post each question separately for better answering.
Answering the above part of your question (before "OR")


(i)Fireflies undergo a chemical reaction in body by reaction of oxygen, calcium, adenosine triphosphate and luciferin to produce an enzyme which glows called bioluminescent enzyme and process is called bioluminescence.
(ii) Fire extinguishers produces a non combustible gas CO₂ by the following reaction
2NaHCO₃ + H₂SO₄ ⇒ Na₂SO₄ + 2H₂O + 2CO2
which helps in stopping fire.

Hope it helps
Regards