Which of the following reactions is used in the preparation of `N_(2)(g)`?

Options

A. `(NH_(4))_(2)Cr_(2)O_(7)overset("heat")(rarr)`
B. `NH_(3)+Ca(OCl)_(2)overset("heat")(rarr)`
C. `NH_(4)Cl+NaNO_(2)overset("heat")(rarr)`
D. All of these

Answer

4

Explanation

A cylinder of `N_(2)`is th eusual source of `N_(2)`in the laboratory ,but in the laboratory ,dinitorgen is prepared by warming a concentrated solution of a ammonium nitrite made in situ from ammonium chloride and sodium nitrite until it decomposes:
`NH_(4)Cl+NaNO_(3)rarrNaCl+NH_(4)NO_(2)overset("warm")rarrN_(2)+2H_(2)O`
it can also be obtained by the thermal decomposition fo ammonium dischromate:
`(NH_(4))_(2)Cr_(2)O_(7)overset(Delta)rarrN_(2)+4H_(2)O+Cr_(2)O_(3)`
`N_(2)` is also obtained by oxidizing `NH_(3)`with calcium hypocholrite.
`4NH_(3)+3Ca(OCl)_(2)rarr2N_(2)+3CaCl_(2)+6H_(2)O`