In an organic compound,phosphorus is estimated as:

The reaction of $Q$ with $PhSNa$ yields an organic compound (major product) that gives a positive Carius test on treatment with $Na_2O_2$ followed by the addition of $BaCl_2$. The correct option$(s)$ for $Q$ is (are):

Which one of the following methods can be used to find out the percentage composition of halogen present in an organic compound?

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

In the Kjeldahl method,$0.35 \ g$ of an organic compound produces ammonia,which is absorbed in $100 \ mL$ of $0.1 \ M \ H_2SO_4$. The excess $H_2SO_4$ requires $154 \ mL$ of $0.1 \ M \ NaOH$ for titration. Calculate the percentage of nitrogen in the compound. (Given atomic masses: $C=12, H=1, O=16, N=14, S=32$)

$A$ sample of $0.125 \ g$ of an organic compound when analysed by Duma's method yields $22.78 \ mL$ of nitrogen gas collected over $KOH$ solution at $280 \ K$ and $759 \ mm \ Hg$. The percentage of nitrogen in the given organic compound is (Nearest integer).
$(a)$ The vapour pressure of water at $280 \ K$ is $14.2 \ mm \ Hg$
$(b)$ $R = 0.082 \ L \ atm \ K^{-1} \ mol^{-1}$