The half-life of first order decomposition of `NH_(4)NO_(3)` is 2.10 hr at 288 K temperature
`NH_(4)NO_(3)(aq)toN_(2)O(g)+2H_(2)O(l)`. If 6.2 of `NH_(4)NO_(3)` is allowed to decompose, the required for `NH_(4)NO_(3)` to decompose 90 % is :
A. 6.978 hr
B. 0.319
C. 0.319 hr
D. None of these
