The variation of the boiling point of the hydrogen halides is in the order HF > HI > HBr >

HCl. What explains the higher boiling point of hydrogen fluoride?

1. The electronegativity of fluorine is much higher than for other elements in the group

2. There is strong hydrogen bonding between HF molecules

3. The bond energy ol HF molecules is greater than in other hydrogen halides

4. The effect of nuclear shielding is much reduced in fluorine which polarises the HF

molecule

Strong reducing behaviour of H₃PO2 is due to -

1. Presence of one-OH group and two P-H bonds

2. High electron gain enthalpy of phosphorus

3. High oxidation state of phosphorus

4. Presence of two-OH groups and one P-H bond

Acidity of diprotic acids in aqueous solutions increases in the order:-

1. H₂S<H₂Se<H₂Te

2. H₂Se<H₂S<H₂Te

3. H₂Te<H₂S<H₂Se

4. H₂Se<H₂Te<H₂S

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 isolated. The gas X is

1. H₂S

2. SO₂

3. CO₂

4. SO₃

When Cl₂ gas reacts with hot and concentrated sodium hydroxide solution, the oxidation

number of chlorine changes from

1. zero to +1 and zero to -5

2. zero to -1 and zero to +5

3. zero to -1 and zero to +3

4. zero to +1 and zero to -3

Which of the following statements is not valid for oxoacids of phosphorus?

1. Orthophosphoric acid s used in the manufacture of triple superphosphate

2. Hypophosphorus acid is a diprotic acid

3. All oxoacids contain tetrahedral four coordinated phosphorus

4. All oxoacids contain at least one P=O unit and one P-OH group

How can one obtain sulphur trioxide?

1. CaSO₄ + C$\stackrel{∆}{\to }$                         

2. Fe₂(SO₄)₃$\stackrel{∆}{\to }$

3. S + H₂SO₄$\stackrel{∆}{\to }$                         

4. H₂SO₄ + PCl₅ $\stackrel{∆}{\to }$

Among the following which is the strongest oxidising agent ?

1. F₂

2. Br₂

3. I₂

4. Cl₂

Which of the statements given below is incorrect?

1. Cl₂O₇ is an anhydride of perchloric acid

2. O₃ molecule is bent

3. ONF is isoelectronic with Anionic NO2

4. OF₂ is an oxide of fluorine

The maximum bond angle at nitrogen is present in which of the following?

1. NO₂

2. NO_2^-

3. NO_2⁺

4. NO3_^-