Answer
405.3k+ views
Hint: When an electron is added to the valence shell of a neutral atom, a certain amount of energy is required or released. This energy is termed as Electron Gain Enthalpy or Electron Enthalpy Value. Electron Gain Enthalpy is opposite to the Ionization Enthalpy (IE). When addition of electrons requires energy, then Electron Gain Enthalpy gets a positive sign and when it releases energy, Electron Gain Enthalpy gets a negative sign.
Complete step by step answer:
In the option A, ${\text{O(g) + e}} \to {{\text{O}}^{\text{ - }}}{\text{(g)}}$, Oxygen is in gaseous state and it is accepting an electron, thus releasing energy. So, its Electron Enthalpy Value is negative.
In the second option B,${\text{N}}{{\text{a}}^{\text{ + }}}{\text{(g) + }}{{\text{e}}^{\text{ - }}} \to {\text{Na(g)}}$, ${\text{N}}{{\text{a}}^{\text{ + }}}$ is in gaseous state. It is accepting an electron and releasing energy. So, again the Electron Enthalpy Value is negative.
In the third option C, ${{\text{O}}^{\text{ - }}}{\text{ + }}{{\text{e}}^{\text{ - }}} \to {{\text{O}}^{{\text{2 - }}}}{\text{(g)}}$, ${{\text{O}}^{\text{ - }}}$ has excess electrons already and an electron is again added. So, the incoming electron will face repulsion because of which energy needs to be given to add this incoming electron. Hence, the energy absorbed in this process. And the Electron Enthalpy Value is positive here.
If we take the option D (${{\text{O}}^{{\text{2 - }}}}{\text{(g)}} \to {{\text{O}}^{\text{ - }}}{\text{(g) + }}{{\text{e}}^{\text{ - }}}$), it’s a reverse process of option C. In this reaction, energy is released.
Thus, the correct option is C (${{\text{O}}^{\text{ - }}}{\text{ + }}{{\text{e}}^{\text{ - }}} \to {{\text{O}}^{{\text{2 - }}}}{\text{(g)}}$).
Note: When an electron is added to an atom. It gets support from the nucleus in the form of nuclear attraction, but it also faces repulsion from other electrons which is called a screening effect. Hence, Electron Gain Enthalpy depends on the element’s nature as well as its requirements.
Complete step by step answer:
In the option A, ${\text{O(g) + e}} \to {{\text{O}}^{\text{ - }}}{\text{(g)}}$, Oxygen is in gaseous state and it is accepting an electron, thus releasing energy. So, its Electron Enthalpy Value is negative.
In the second option B,${\text{N}}{{\text{a}}^{\text{ + }}}{\text{(g) + }}{{\text{e}}^{\text{ - }}} \to {\text{Na(g)}}$, ${\text{N}}{{\text{a}}^{\text{ + }}}$ is in gaseous state. It is accepting an electron and releasing energy. So, again the Electron Enthalpy Value is negative.
In the third option C, ${{\text{O}}^{\text{ - }}}{\text{ + }}{{\text{e}}^{\text{ - }}} \to {{\text{O}}^{{\text{2 - }}}}{\text{(g)}}$, ${{\text{O}}^{\text{ - }}}$ has excess electrons already and an electron is again added. So, the incoming electron will face repulsion because of which energy needs to be given to add this incoming electron. Hence, the energy absorbed in this process. And the Electron Enthalpy Value is positive here.
If we take the option D (${{\text{O}}^{{\text{2 - }}}}{\text{(g)}} \to {{\text{O}}^{\text{ - }}}{\text{(g) + }}{{\text{e}}^{\text{ - }}}$), it’s a reverse process of option C. In this reaction, energy is released.
Thus, the correct option is C (${{\text{O}}^{\text{ - }}}{\text{ + }}{{\text{e}}^{\text{ - }}} \to {{\text{O}}^{{\text{2 - }}}}{\text{(g)}}$).
Note: When an electron is added to an atom. It gets support from the nucleus in the form of nuclear attraction, but it also faces repulsion from other electrons which is called a screening effect. Hence, Electron Gain Enthalpy depends on the element’s nature as well as its requirements.
Recently Updated Pages
How many sigma and pi bonds are present in HCequiv class 11 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Why Are Noble Gases NonReactive class 11 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let X and Y be the sets of all positive divisors of class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x and y be 2 real numbers which satisfy the equations class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x 4log 2sqrt 9k 1 + 7 and y dfrac132log 2sqrt5 class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x22ax+b20 and x22bx+a20 be two equations Then the class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Trending doubts
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
At which age domestication of animals started A Neolithic class 11 social science CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Which are the Top 10 Largest Countries of the World?
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Give 10 examples for herbs , shrubs , climbers , creepers
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference Between Plant Cell and Animal Cell
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Write a letter to the principal requesting him to grant class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Change the following sentences into negative and interrogative class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Fill in the blanks A 1 lakh ten thousand B 1 million class 9 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)