Question
Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first? Justify your answer.
✓
Answer
For oxygen atom:
$\text{O}(\text{e}) + \text{e}^{-} \rightarrow \text{O}^{-}(\text{g}) (\Delta\text{eg} \text{H} = -141 \ \text{kj}\ \text{mol}^{-})$
$\text{O} (\text{g}) + \text{e}^{-} \rightarrow \text{O} ^{2-} (\text{g}) (\Delta\text{eg}\text{H} = + 780\ \text{KJ}\ \text{mol}^{-1})$
The first electron gain enthalpy of oxygen is negative because energy is released when a gaseous atom accepts an electron to form monovalent anion. The second electron gain enthalpy is positive because energy is needed to overcome the force of repulsion between monovalent anion and second incoming electron.
$\text{O}(\text{e}) + \text{e}^{-} \rightarrow \text{O}^{-}(\text{g}) (\Delta\text{eg} \text{H} = -141 \ \text{kj}\ \text{mol}^{-})$
$\text{O} (\text{g}) + \text{e}^{-} \rightarrow \text{O} ^{2-} (\text{g}) (\Delta\text{eg}\text{H} = + 780\ \text{KJ}\ \text{mol}^{-1})$
The first electron gain enthalpy of oxygen is negative because energy is released when a gaseous atom accepts an electron to form monovalent anion. The second electron gain enthalpy is positive because energy is needed to overcome the force of repulsion between monovalent anion and second incoming electron.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Consider the following structure:
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\text{O}}\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \|\\\ ^1\text{C}_3-\ ^2\text{CH}_2-\ ^3\text{C}-\ ^4\text{C}_2-\ ^5\text{C}\equiv\ ^6\text{CH}$
→$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\text{O}}\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \|\\\ ^1\text{C}_3-\ ^2\text{CH}_2-\ ^3\text{C}-\ ^4\text{C}_2-\ ^5\text{C}\equiv\ ^6\text{CH}$
- How many σ and π-bonds are present in this compound?
- Arrange carbon no. 2, 3, 5 in decreasing order of s-character.
- Which atoms have same hybrid state?
Describe what you need to do in the laboratory to test
i. the law of conservation of mass,
ii. the law of definite proportion
iii. the law of multiple proportions.
i. the law of conservation of mass,
ii. the law of definite proportion
iii. the law of multiple proportions.
The following techniques are used to quantitatively estimate extra elements in organic compound. Identify the name of the method and the element estimated by this method.
- A known mass of an organic compound is heated with fuming HNO3 in presence of AgNO3.
- Organic compound is heated with dry copper oxide in atmosphere of CO2.
- Organic compound is heated with conc. H2SO4.
Match the following graphical variation with their description.
What is the number of photons of light with wavelength 4000 pm which provides 1 J of energy?
How much sugar (C12H22O11) will be required if each person on the earth is given 1015 moles of sugar per day. Population of the earth is 3 × 1010.
- What is the state of hybridisation of nitrogen in $\text{NH}_4^+$ ion?
- Draw the shape of PH3 and SF6 according to VSEPR theory.
- Which hybrid orbitals are used by carbon atoms in $\text{CH}_3-\text{CHO}?$
Balance the following equation,
$
Fe+H_2 O \longrightarrow Fe_3 O_4+H_2
$
→$
Fe+H_2 O \longrightarrow Fe_3 O_4+H_2
$
With help of following values calculate energy of $> C = C <$ bond :
$
\begin{array}{l}
2 C(s)+2 H_2(g)=C_2 H_4(g) ; \Delta H=52.6 kJ \\
C(s) \rightarrow C(g) ; \Delta H=716.68 kJ \\
H_2(g)=2 H(g) ; \Delta H=435.84 kJ \\
\text { and } C-H \text { bond energy }=+413 kJ
\end{array}
$
→$
\begin{array}{l}
2 C(s)+2 H_2(g)=C_2 H_4(g) ; \Delta H=52.6 kJ \\
C(s) \rightarrow C(g) ; \Delta H=716.68 kJ \\
H_2(g)=2 H(g) ; \Delta H=435.84 kJ \\
\text { and } C-H \text { bond energy }=+413 kJ
\end{array}
$