The electrophilic bromination or chlorination of benzene requires Lewis acid along with the halogen.
<h3>
What is bromination of benzene?</h3>
The bromination or chlorination of benzene is an example of an electrophilic aromatic substitution reaction. 
During the reaction, the bromine forms a sigma bond to the benzene ring, yielding an intermediate. Subsequently a  a proton is removed from the intermediate to form a substituted benzene ring.
This reaction is achieved with the help of Lewis acid as catalysts.
Thus, the electrophilic bromination or chlorination of benzene requires Lewis acid along with the halogen.
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Answer:
Option B
Explanation:
- For Option A the state is not changing but just has different look now. 
- For Option B the state is changing from gas to liquid drops due to cold glass 
- For Option C it hasn't changed state as both corn and flower is solid
- For Option D paper and ash are both solids
Therefore our answer must be Option B 
 
        
             
        
        
        
The element "X" is "O" (oxygen).
<h3>Calculation:</h3>
Given,
Chemical formula = Na₂CX₃
Formula mass = 106 amu
Molar mass of Na = 23 amu
Molar mass of C = 12 amu
To find,
Element X =?
We will equate the equation as follows,
2(23) + 12 + 3(y) = 106
46 + 12 + 3y =106
58 + 3y = 106
3y = 106 - 58
3y = 48
y = 48/3
y = 16 
We know that Oxygen has molecular mass of 16. Therefore the element "X" is "O".
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