While estimating the nitrogen present in an organic compound by Kjeldahl's method, the ammonia evolved from $$0.25 \mathrm{~g}$$ of the compound neutralized $$2.5 \mathrm{~mL}$$ of $$2 \,\mathrm{M} \,\mathrm{H}_{2} \mathrm{SO}_{4}$$. The percentage of nitrogen present in organic compound is ______________.

The number of sp³ hybridised carbons in an acyclic neutral compound with molecular formula C₄H₅N is ___________.

In the given reaction

The number of chiral carbon/s in product A is ___________.

The total number of functions,

$$ f:\{1,2,3,4\} \rightarrow\{1,2,3,4,5,6\} $$ such that $$f(1)+f(2)=f(3)$$, is equal to :