MCQ
Given below are two statements. One is labelled as Assertion $A$ and the other is labelled as Reason $R$.

Assertion $A$ : The first ionization enthalpy for oxygen is lower than that of nitrogen.

Reason $R$ : The four electrons in $2 p$ orbitals of oxygen experience more electron-electron repulsion.

In the light of the above statements, choose the correct answer from the options given below.

  • Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$.
  • B
    Both $A$ and $R$ are correct but $R$ is NOT the correct explanation of $A$.
  • C
    $A$ is correct but $R$ is not correct.
  • D
    $A$ is not correct but $R$ is correct

Answer

Correct option: A.
Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$.
a
Ionisation energy $= N > O$.

In oxygen atom, $2$ of the $42 p$ electrons must occupy the same $2 p$ orbital resulting in an increased electron electron-repulsion.

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