The p-Block Elements

The catalyst and promoter respectively used in the Haber's process of industrial synthesis of ammonia are

• Mo,V₂O₅

• V₂O_5, Fe

• Fe, Mo

• Mo, Fe

Bond energy of Cl₂, Br₂ and I₂ follow the order

• Cl₂ >Br₂ > I₂

• Br₂ >Cl₂ > I₂

• I₂ > Br₂ >Cl₂

• I₂ > Cl₂ >Br₂

Assertion (A): The boiling points of noble gases increases from He to Xe.

Reason (R): The interatomic van der Waals' attractive forces increases from He to Xe.

The correct answer is:

• Both (A) and (R) are true, and (R) is the correct explanation of (A).

• Both (A) and (R) are true, and (R) is not the correct explanation of (A).

• (A) is true but (R) is not true.

• (A) is not true but (R) is true.

The product(s) formed when H₂O₂ reacts with disodium hydrogen phosphate is

• P₂O₅.Na₃PO₄

• Na₂HPO₄.H₂O₂

• NaH₂PO₄, H₂O

• Na₂HPO₄.H₂O

Which one of the following is used in the preparation of cellulose nitrate ?

• KNO₃

• HNO₃

• KNO₂

• HNO₂

The oxoacid of sulphur which contains two sulphur atoms in different oxidation states is

• pyrosulphurous acid

• hyposulphurous acid

• pyrosulphuric acid

• persulphuric acid

The structure of XeOF₄, is

• trigonal bipyramidal

• square pyramidal

• square planar

• pyramidal

Assertion (A) : Noble gases have very low boiling points.

Reason (R) : All noble gases have general electronic configuration of ns² np⁶ (except He).

• Both (A) and (R) are true and (R) is the correct explanation of (A).

• (A) is false but (R) is true.

• (A) is true but (R) is false.

• Both (A) and (R) are true and (R) is not the correct explanation of (A).

The charring of sugar takes place when treated with concentrated H₂SO₄. What is the type of reaction involved in it?

• Dehydration reaction

• Hydrolysis reaction

• Addition reaction

• Disproportionation reaction

The increasing order of the atomic radius of Si, S, Na, Mg, Al is

• S < Si< Al< Mg< Na

• Na< Mg < Si< Al< S

• Na< Mg< Si< Al < S

• Na< Mg< Al< Si< S