Title

  Pure nitrogen trifluoride (NF3) is used as a cleaning agent in the production of integrated circuits and large-screen liquid crystal displays (TFT-LCD). Nitrogen trifluoride can undergo redox reactions with water vapor in humid air, and the products of the reaction include: HF, NO, and HNO3. Please answer the following questions according to the requirements:

  （1）The electronic formula of NF3 is          .

  （2）Write the chemical equation for this reaction.                .

  （3）NF3 is a colorless, odorless gas, but once NF3 leaks into the air, it is still easy to detect. You judge that the phenomenon when this gas leaks is                    .

  （4）Once NF3 leaks, the pollution can be reduced by spraying a solution.

  （5）A method for producing NF3: fluorine gas reacts with liquid ammonium bifluoride (NH4HF2) to produce NF3. Write the chemical equation for this reaction:

  Answer

  （1）NF3

  （2） 3NF3+5 H2O  =  2 NO+HNO3+9 HF .

  （3）Produces reddish-brown gas, produces white mist.

  （4）NaOH

  （5）3F2 + NH4HF2 = NF3 + 5HF