Tag: chemistry

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Multiple choice chemistry petrochemicals and polymers petroleum properties of alkanes petroleum and natural gas rocks and minerals

The final product in the following reaction can be used as, $4CH _3-CH _2-Cl+4Na+Pb \rightarrow$

  1. anaesthatic

  2. narcotics

  3. analgesic

  4. antiknocking agent
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • The final product of this reaction is $(CH _3CH _2) _4Pb$ [tetraethyl lead (TEL)].
$4CH _3-CH _2-Cl + 4Na + Pb \rightarrow (CH _3CH _2) _4Pb$
It is also used as an antiknocking agent in fuels for automobiles.

Multiple choice chemistry p- block elements-ii group 16 elements - general properties group 16 elements - trends in chemical properties group 16 elements

Group 16 elements have a lower value of first ionization enthalpy as compared to group 15 elements because:

  1. half filled p-orbitals in group 15 elements are more stable

  2. group 16 elements have smaller size than group 15 elements

  3. group 16 elements contain double bond while group 15 elements have a triple bond

  4. group 16 elements have more number of electrons in p-orbitals
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Group 16 elements have a lower value of first ionization enthalpy as compared to group 15 elements. As group 15 elements have half filled p-orbital due to which group 15 have got extra stability.

Multiple choice chemistry p- block elements-ii group 16 elements - general properties group 16 elements - trends in chemical properties group 16 elements

A group 16 element exists in the monoatomic state in the metallic lattices. It also exists in two crystalline forms. The metal is:

  1. Po

  2. S

  3. Se

  4. Te
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

polonium has two metallic allotropes, the $\alpha $ atom has the simple cubic structure in a single atom basis at STP and $\beta $ atom of it has rhombohedral structure. Po belongs to group 16.

Multiple choice chemistry p- block elements-ii group 16 elements - general properties group 16 elements - trends in chemical properties group 16 elements

Arrange the following elements in order of their increasing ionisation energies $O, S, Se, Te, Po$ :

  1. $Se, Te, S, Po, O$
  2. $O, S, Se, Te, Po$
  3. $Po, Te, Se, S, O$
  4. $Te, O, S, Po, Se$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ionisation energy decreases from top to bottom in a group. So increasing order will be
Po < Te < Se < S < O

Multiple choice chemistry p- block elements-ii group 16 elements - general properties group 16 elements - trends in chemical properties group 16 elements

Which is the following order is INCORRECT?

  1. ${ Na } _{ 2 }O<{ SiO } _{ 2 }<{ Cl } _{ 2 }{ O } _{ 7 }$ Acidic character order
  2. ${ PH } _{ 3 }<{ AsH } _{ 3 }<{ SbH } _{ 3 }$ basic character order
  3. ${ PH } _{ 3 }<{ AsH } _{ 3 }={ SbH } _{ 3 }$ acidic character order
  4. $I{ EA } _{ 1 }$>$I{ EA } _{ 2 }$>$I{ EA } _{ 1 }$ Successive electron affinity order.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The basic character of hydrides of group 15 elements decreases down the group (NH3 > PH3 > AsH3 > SbH3) because the lone pair becomes more diffuse. Thus, the order PH3 < AsH3 < SbH3 is incorrect.

Multiple choice chemistry p- block elements-ii group 16 elements - general properties group 16 elements - trends in chemical properties group 16 elements

Group $16$ element are called:

  1. Carbon family

  2. Chalcogen family

  3. Halogen family

  4. Nitrogen family
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The chalcogens are the chemical elements in the group $16$ of the periodic table. 

This group is also known as the oxygen family. It consists of the elements oxygen, sulfur, selenium, tellurium, and the radioactive element polonium. 

Hence, the correct answer is option $B$.