p-Block Elements

JEE Chemistry · 225 questions · Page 2 of 23 · Click an option or "Show Solution" to reveal answer

Q11

When metal ‘M’ is treated with NaOH, a white gelatinous precipitate ‘X’ is obtained, which is soluble in excess of NaOH. Compound ‘X’ when heated strongly gives an oxide which is used in chromatography as an adsorbent. The metal ‘M’ is

A Fe

B Zn

C Ca

D Al

Correct Answer

Option D

Solution

Among the given Metal Al is the correct answer. Al2O3 is used as an absorbed in chromatography.

Q12

In graphite and diamond, the percentage of p-characters of the hybrid orbitals in hybridisation are respectively :

A 33 and 25

B 33 and 75

C 50 and 75

D 67 and 75

Correct Answer

Option D

Solution

Hybridization of carbon in graphite is sp2. So, % of p - in graphite =

{2 \over 3} \times 100

= 67% Hybridization of carbon in diamond is sp3 . So, % of p - in diamond =

{3 \over 4} \times 100

= 75%

Q13

A white sodium salt dissolves readily in water to give a solution which is neutral to litmus. When silver nitrate solution is added to the aformentioned solution, a white precipitate is obtained which does not dissolve in dil. nitric acid. The anion is :

A CO32-

B SO42-

C Cl-

D S2-

Correct Answer

Option C

Solution

The anion is Cl− . Chloride ion reacts with AgNO3 to give a white precipitate. AgCl is insoluble in dil. nitric acid.

Q14

The one that is extensively used as a piezoelectric material is :

A tridymite

B amorphous silica

C quartz

D mica

Correct Answer

Option C

Solution

Those materials which produce electricity under mechanical stress are called piezoelectric material.

Quartz is an example of piezoelectric material.

Q15

Good reducing nature of H3PO2 is attributed to the presence of :

A Two P

-

OH bonds

B One P

-

H bond

C Two P

-

H bonds

D One P

-

OH bond

Correct Answer

Option C

Solution

H3PO2 is good reducing agent due to presence of two P $-$ H bonds.

Q16

Among the following reactions of hydrogen with halogens, the one that requires a catalyst is :

A H2 + Br2

\to

2HBr

B H2 + Cl2

\to

2HCl

C H2 + F2

\to

2HF

D H2 + I2

\to

2HI

Correct Answer

Option D

Solution

The reaction which has slow reactivity requires catalyst.

Among halogens reactivity order is F2 > Cl2 > Br2 > I2 So, H2 + I2 $\to$ 2HI, this reaction requires a catalyst.

Q17

The chloride that CANNOT get hydrolysed is :

A SnCl4

B SiCl4

C PbCl4

D CCl4

Correct Answer

Option D

Solution

CCl4 cannot get hydrolysed as it does not have dorbitals and cannot extend its covalency above four.

Q18

The relative stability of +1 oxidation state of group 13 elements follows the order :

A Tl < In < Ga < Al

B Al < Ga < TI < In

C AI < Ga < In < TI

D Ga < AI < In < TI

Correct Answer

Option C

Solution

Inert pair effect gradually increases down the group.

Hence, stability of lower oxidation state increases down the group.

$\therefore$ AI < Ga < In < TI

Q19

The hydride that is NOT electron deficient :

A B2H6

B AlH3

C GaH3

D SiH4

Correct Answer

Option D

Solution

SiH4 has complete octet hence it is not an electron deficient hydride.

Q20

Iodine reacts with concentrated HNO3 to yield Y along with other products. The oxidation state of iodine in Y, is :

A 3

B 1

C 7

D 5

Correct Answer

Option D

Solution

I2 + 10HNO3 $\to$ 2HIO3 (Y) + 10NO2 + 4H2O Let In HIO3 oxidation state of iodine is x. $\therefore$ +1 + x + 3(–2) = 0 $\Rightarrow$ x = +5

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