What are the advantages of the $CHN$ elemental analysis method?

$1.4 \ g$ of an organic compound was digested according to Kjeldahl's method and the ammonia evolved was absorbed in $60 \ mL$ of $M/10 \ H_2SO_4$ solution. The excess sulphuric acid required $20 \ mL$ of $M/10 \ NaOH$ solution for neutralization. The percentage of nitrogen in the compound is

In the estimation of sulphur by Carius method,$0.468 \,g$ of an organic sulphur compound afforded $0.668 \,g$ of barium sulphate. Find out the percentage of sulphur in the given compound. (in $\%$)

Calculate the percentage of nitrogen in $0.25 \ g$ of an organic compound if $38 \ cm^3$ of $N_2$ gas is evolved at $300 \ K$ and $96 \ kPa$ pressure. (Given: $1 \ atm = 101.3 \ kPa$)

During $S$ estimation,$160 \ mg$ of an organic compound gives $466 \ mg$ of barium sulphate. The percentage of Sulphur in the given compound is . . . . . . $\%.$ (Given molar mass in $g \ mol^{-1}$ of $Ba: 137, S: 32, O: 16$)

Explain the principle of estimation of oxygen in an organic compound.