Select the correct statement(s).

Options

A. `PAN` is formed in a chain reaction
B. `PAN` is a product of photochemical smog
C. `NO_(2)` contributes to haze
D. All of the above are correct statement

Answer

D

Explanation

Undurnt fuel and `NO` are emitted from automobiles. In presence of sunlight, `NO` change to `NO_(2)` which in turn absorbs energy from sunlight and breaks up into `NO` and `O` and a chain reaction starts .
`NO_(2) rarr NO+O`
`O+O_(2) rarr O_(3)`
`NO+O_(3) rarr O_(2) + NO_(3)`
`HC("Hydrocarbon , fuel")+O_(3) rarr CHCHO+CH_(2) -=CHCHO`

`NO_(2)` is a brown gas and at sufficiently hight levels can contribute to haze.