The number of moles of $CuO$ that will be utilized in the Dumas method for the estimation of nitrogen in a sample of $57.5 \ g$ of $N,N$-dimethylaminopentane is $..... \times 10^{-2}$. (Nearest integer)

In sulphur estimation,$0.471 \ g$ of an organic compound gave $1.4439 \ g$ of barium sulphate. The percentage of sulphur in the compound is $.............$ (Nearest Integer) (Given: Atomic mass $Ba: 137 \ u, S: 32 \ u, O: 16 \ u$)

In the sulphur estimation,$0.20 \ g$ of a pure organic compound gave $0.40 \ g$ of barium sulphate. The percentage of sulphur in the compound is $.......... \times 10^{-1} \%$. $(Molar \ mass : O=16, S=32, Ba=137 \ g \ mol^{-1})$

In the Carius method, $0.2425 \ g$ of an organic compound gave $0.5253 \ g$ of silver chloride. The percentage of chlorine in the organic compound is: (in $\%$)

What is the reason for passing dry air through the combustion tube during the estimation of $C$ and $H$?

In the estimation of nitrogen,$0.3 \ g$ of an organic compound was digested,and the evolved ammonia was passed into $100 \ mL$ of $0.1 \ M \ H_2SO_4$. The excess acid required $20 \ mL$ of $0.5 \ M \ NaOH$ for complete neutralization. What is the organic compound?