A solid (A) reacts with strong aqueous NaOH, liberating a foul smelling gas (B), which spontaneously burns in the air, giving smoky rings. A and B are, respectively:
1. P4 (red) and PH3
2. P4 (white) and PH3
3. S8 and H2S
4. P4 (white) and H2S
The respective oxidation states of P in H4P2O5, H4P2O6, and H4P2O7 are:
1. | +3, +5, and +4 | 2. | +5, +3, and +4 |
3. | +5, +4, and +3 | 4. | +3, +4, and +5 |
A balanced chemical equation for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen is:
1. | 4NH3 + \(\underset{\text{From air}}{5O_2} \) \(\xrightarrow[\text{500 K; 9 bar}]{\text{Pt / Rh gauge catalyst}}\) 4NO + 6H2O |
2. | 3NH4 + \(\underset{\text{From air}}{5O_2} \) \(\xrightarrow[\text{500 K; 9 bar}]{\text{Pt / Rh gauge catalyst}}\) 3NO + 6H2O |
3. | 4NH3 + \(\underset{\text{From air}}{5O_2} \) \(\xrightarrow[\text{cold}]{\text{no catalyst}}\) 4NO + 6H2O |
4. | 3NH4 + \(\underset{\text{From air}}{5O_2} \) \(\xrightarrow[\text{cold}]{\text{no catalyst}}\) 3NO + 6H2O |
The correct structure of pyrophosphoric acid is:
1. | 2. | ||
3. | 4. |
PH3 forms bubbles when passed slowly through water but NH3 gets dissolved in water, because:
1. | NH3 forms an H-bond with water, so it is soluble but PH3 does not form an H-bond. |
2. | NH3 does not form an H-bond with water, so it is soluble but PH3 does form an H-bond. |
3. | NH3 and PH3 both form H-bond with water. |
4. | NH3 and PH3 both do not form H-bond with water. |
Incorrect order among the following is:
1. | F2 > Cl2 > Br2 > I2 | Oxidising power |
2. | F < Cl > Br > I | Electron gain enthalpy |
3. | F2 > Cl2 > Br2 > I2 | Bond dissociation energy |
4. | F> Cl > Br > I | Electronegativity |
The disproportionation reaction of is as follows:
X and Y in the above reaction are:
1. H3PO2, HPO2
2. H3PO4, PH3
3. H2PO6, PO3
4. None of the above.
The correct increasing order of basic strength of hydrides:
1. BiH3 \(\simeq \) SbH3 < AsH3 < PH3 < NH3
2. BiH3 > NH3 > PH3 > SbH3 > AsH3
3. SbH3 < AsH3 < PH3 < NH3 < BiH3
4. AsH3 > NH3 > PH3 > SbH3 > BiH3
An element that does not show allotropy is:
1. Nitrogen
2. Phosphorus
3. Antimony
4. Arsenic
A brown ring formed in the ring test for ion is due to the formation of:
1. [Fe(H2O)5(NO)]2+
2. FeSO4.NO2
3. [Fe(H2O)4(NO)2]2+
4. FeSO4.HNO3