Qualitative and Quantitative Analysis — Prelims Questions

In Lassaigne's test for the detection of nitrogen in an organic compound, the Prussian blue color is formed due to the formation of:

A 0.25 g sample of an organic compound containing carbon, hydrogen, and oxygen was subjected to complete combustion. The water produced weighed $0.18,\text{g}$ and carbon dioxide weighed $0.44,\text{g}$. What is the percentage of carbon in the compound?

Which of the following compounds cannot be analyzed for nitrogen using Kjeldahl's method?

In the Carius method for the estimation of sulfur, $0.32,\text{g}$ of an organic compound yielded $0.466,\text{g}$ of barium sulfate (BaSO$_4$). The percentage of sulfur in the compound is (Atomic mass of S = 32, Ba = 137, O = 16).

Which of the following tests is used for the qualitative detection of phosphorus in an organic compound?

In the Dumas method for the estimation of nitrogen, $0.35,\text{g}$ of an organic compound gave $50,\text{mL}$ of nitrogen collected at $27^circ\text{C}$ and $715,\text{mm}$ Hg pressure. If the aqueous tension at $27^circ\text{C}$ is $15,\text{mm}$ Hg, what is the volume of nitrogen at STP?

Which of the following statements about the detection of sulfur in an organic compound by Lassaigne's test is INCORRECT?