Which gas is produced in the atmosphere due to lightning?

On heating ammonium dichromate,the gas evolved is

Which of the following statements is incorrect for nitrogen?

Under which conditions can active nitrogen be obtained from $N_2$ gas using an electric spark?

What is the product obtained when orthophosphoric acid $(H_3PO_4)$ is heated to a high temperature?

Identify the $INCORRECT$ statement$(s)$ among the following:
$(I)$ Moist ammonia gas can be dried by using anhydrous $CaCl_2$
$(II)$ Phosphine is a weaker base than ammonia
$(III)$ $R_3SiCl$ produces very complex cross-linked polymeric silicone on hydrolysis
$(IV)$ When metallic copper reacts with $6 \ M$ $HNO_3$,$NO_2$ is the only product