Examkin

Question

Difficulty: Very hardNitrogen Gas, Nitrogen Cycle, and Oxides of Nitrogen

Under identical conditions of temperature and pressure, a neutral oxide of nitrogen diffuses 1.211.21 times faster than carbon(IV) oxide (CO2CO_2). Which of the following is a characteristic chemical property of this oxide of nitrogen? (Relative atomic masses: C=12,N=14,O=16\text{Relative atomic masses: } C = 12, N = 14, O = 16)

  1. It reacts rapidly with atmospheric oxygen at room temperature to form reddish-brown fumes.Answer
  2. B
    It relights a glowing wooden splint almost as vigorously as oxygen gas.
  3. C
    It dissolves readily in water at STP to produce an acidic solution of trioxonitrate(V) acid.
  4. D
    It readily condenses near room temperature into a pale yellow liquid undergoing reversible dimerization.

Answer

The gas reacts rapidly with atmospheric oxygen at room temperature to form reddish-brown fumes.
Using Graham's law of diffusion, the molar mass of the unknown gas is calculated as 441.212≈30.0 g mol−1\frac{44}{1.21^2} \approx 30.0\text{ g mol}^{-1}, which corresponds uniquely to nitrogen(II) oxide (NONO). A defining chemical test for NONO is its immediate oxidation by air to give reddish-brown fumes of nitrogen(IV) oxide (NO2NO_2).

Step-by-Step Solution

1
Calculate the molar mass of carbon(IV) oxide (CO2CO_2).
M(CO2)=12+2(16)=44 g mol−1M(CO_2) = 12 + 2(16) = 44\text{ g mol}^{-1}.
Graham's law requires the molar mass of the reference gas.
2
Apply Graham's law of diffusion to determine the molar mass of the unknown nitrogen oxide (MxM_x).
RxRCO2=M(CO2)Mx  ⟹  1.21=44Mx  ⟹  (1.21)2=44Mx  ⟹  Mx=441.4641≈30.0 g mol−1\frac{R_x}{R_{CO_2}} = \sqrt{\frac{M(CO_2)}{M_x}} \implies 1.21 = \sqrt{\frac{44}{M_x}} \implies (1.21)^2 = \frac{44}{M_x} \implies M_x = \frac{44}{1.4641} \approx 30.0\text{ g mol}^{-1}.
The rate of diffusion of a gas is inversely proportional to the square root of its molar mass.
3
Identify the formula of the nitrogen oxide with a molar mass of 30 g mol−130\text{ g mol}^{-1}.
For nitrogen(II) oxide (NONO), M(NO)=14+16=30 g mol−1M(NO) = 14 + 16 = 30\text{ g mol}^{-1}.
Matching the calculated molar mass to known oxides of nitrogen (N2O=44N_2O = 44, NO=30NO = 30, NO2=46NO_2 = 46).
4
Determine the key chemical property of nitrogen(II) oxide (NONO).
Nitrogen(II) oxide (NONO) is a colorless neutral gas that reacts spontaneously with oxygen in air to form brown nitrogen(IV) oxide (2NO+O2→2NO22NO + O_2 \rightarrow 2NO_2).
To select the correct property corresponding to NONO.

Key Concept

Graham's Law of Diffusion and Chemical Properties of Oxides of Nitrogen
Estimated Time:2m 0s
Rate this question

Topics

Nitrogen Gas, Nitrogen Cycle, and Oxides of Nitrogen

More questions from this topic