p-Block Elements — Page 22 | JEE Chemistry

Q211

The set that represents the pair of neutral oxides of nitrogen is :

A NO and N2O

B N2O and NO2

C NO and NO2

D N2O and N2O3

Correct Answer

Option A

Solution

NO and N2O are neutral oxides and N2O3 , NO2 and N2O5 are acidic oxides.

Q212

The correct statement about B2H6 is :

A Its fragment, BH3, behaves as a Lewis base.

B All B

-

H

-

B angles are of 120

^\circ

.

C The two B

-

H

-

B bonds are not of same length.

D Terminal B

-

H bonds have less p-character when compared to bridging bonds.

Correct Answer

Option D

Solution

Terminal B – H bonds are shorter than the bridging B – H bonds which shows that the terminal B – H bonds have greater s-character and less p-character.

Q213

Number of Cl = O bonds in chlorous acid, chloric acid and perchloric acid respectively are :

A 3, 1 and 1

B 4, 1 and 0

C 1, 1 and 3

D 1, 2 and 3

Correct Answer

Option D

Solution

The structure of chlorous acid, chloric acid, and perchloric acid are shown below

Q214

The incorrect statement is :

A Cl2 is more reactive than ClF.

B F2 is more reactive than ClF.

C On hydrolysis ClF forms HOCl and HF.

D F2 is a stronger oxidizing agent than Cl2 in aqueous solution.

Correct Answer

Option A

Solution

(i) Reactivity order : F2 > ClF (inter halogen) > Cl2 (ii) ClF + H2O $\to$ HOCl + HF (iii) Oxidizing power is aqueous solution F2 > Cl2 > Br2 > I2

Q215

The number of non-ionisable hydrogen atoms present in the final product obtained from the hydrolysis of PCl5 is :

A 0

B 2

C 1

D 3

Correct Answer

Option A

Solution

Here all hydrogens are ionisable. $\therefore$ Answer is zero.

Q216

Chalcogen group elements are :

A Se, Tb and Pu.

B Se, Te and Po.

C S, Te and Pm.

D O, Ti and Po.

Correct Answer

Option B

Solution

Group 16/oxygen family is known as Chalcogens the members are O, S, Se, Te, Po

Q217

In which one of the following molecules strongest back donation of an electron pair from halide to boron is expected?

A BCl3

B BF3

C BBr3

D BI3

Correct Answer

Option B

Solution

Type of back bonding

\begin{array}{lll}{B{F_3}} & {BCl} & {BB{r_3}} & {B{I_3}} \\ {(2p\pi - 2p\pi )} & {(2p\pi - 3p\pi )} & {(2p\pi - 4p\pi )} & {(2p\pi - 5p\pi )} \end{array}

Therefore back bonding strength is as follows BF3 > BCl > BBr3 > BI3

Q218

Which one of the following is formed (mainly) when red phosphorus is heated in a sealed tube at 803 K?

A White phosphorus

B Yellow phosphorus

C

\beta

-Black phosphorus

D

\alpha

-Black phosphorus

Correct Answer

Option D

Solution

When red phosphorus is heated in a sealed tube at 803 K, $\alpha$ -Black phosphorus is formed.

Q219

Aqueous solution of which of the following boron compounds will be strongly basic in nature?

A NaBH4

B LiBH4

C B2H6

D Na2B4O7

Correct Answer

Option D

Solution

Na_{2}B_{4}O_{7}+7H_{2}O\longrightarrow 2H_{3}BO_{3}+2Na\left[ B\left( OH\right)_{4} \right]

Aqueous solution of borax is buffer whose pH

\simeq

9 Other compounds are less basic than this.

Q220

The element that shows greater ability to form p

\pi

-p

\pi

multiple bonds, is :

A Si

B Ge

C C

D Sn

Correct Answer

Option C

Solution

In carbon family size of carbon is smallest.

A size of carbon atom is small, so between 2p orbital of two carbon atom effective overlapping happens.

But when size of atom increases then effective overlapping does not happens between atoms.

That is why in carbon family, C will have strongest p $\pi$ $-$ p $\pi$ bond.