The number of acidic protons in H₃PO₃ are:

• 0

• 1

• 2

• 3

1292.

In the brown ring complex [Fe(H₂O)₅(NO)]SO₄, nitric oxide behaves as:

• NO⁺

• neutral NO molecule

• NO^-

• NO^2-

The hydrides of the first elements in groups 15-17, namely NH₃, H₂O and HF respectively show abnormally high values for melting and boiling points. This is due to

• small size of N, O and F

• the ability to form extensive intermolecular H-bonding

• the ability to form extensive intramolecular H-bonding

• effective van der Waals' interaction

Roasting of sulphides gives the gas X as a by-product. This is a colourless gas with choking smell of burnt sulphur. and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic acts as a reducing agent and its acid has never been insolated. The gas X is

• H₂S

• SO₂

• CO₂

• SO₃

Among the following observations, the correct one that differentiates between SO${}_3^{2-}$ and SO${}_4^{2-}$ is

• both form precipitate with BaCl₂, SO${}_3^{2-}$ dissolves in HCl but SO${}_4^{2-}$ does not

• SO${}_3^{2-}$ forms precipitate with BaCl₂, SO${}_4^{2-}$ does not

• SO${}_4^{2-}$ forms precipitate with BaCl₂, SO${}_3^{2-}$ does not

• both form precipitate with BaCl₂, SO${}_4^{2-}$ dissolves in HCl but SO${}_3^{2-}$ does not

Which is the strongest acid in the following?

• H₂SO₄

• HClO₃

• HClO₄

• H₂SO₃

Which one of the following is not true at room temperature and pressure?

• P₄O₁₀ is white solid

• SO₂ is a colourless gas

• SO₃ is a colourless gas

• NO₂ is a brown gas

An element belongs to group 15 and third period of the Periodic Table. Its electronic configuration will be:

• 1s²2s²2p³

• 1s²2s²2p⁴

• 1s²2s²2p⁶3s²3p³

• 1s²2s²2p⁶3s²3p²

Which one of the following is paramagnetic?

• N₂

• NO

• CO

• O₃

Which of the following is used to prepare Cl₂ gas at room temperature from concentrated HCl?

• MnO₂

• H₂S

• KMnO₄

• Cr₂O₃