The incorrect statement is
- The first ionization enthalpy of K is less than that of Na and Li.
- Xe does not have the lowest first ionization enthalpy in its group.
- The first ionization enthalpy of element with atomic number 37 is lower than that of the element with atomic number 38.
- The first ionization enthalpy of Ga is higher than that of the d-block element with atomic number 30.
The Correct Option is D
Solution and Explanation
On moving down in a group ionisation energy decrease
∴ First ionisation enthalpy order is \(Li > Na > K\)
\(Zn\) has more ionisation energy as compared to Ga because of their pseudo-inert gas configuration.
The correct answer is (D): The first ionization enthalpy of \(Ga\) is higher than that of the d-block element with atomic number \(30\).
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Concepts Used:
Enthalpy change
Enthalpy Change refers to the difference between the heat content of the initial and final state of the reaction. Change in enthalpy can prove to be of great importance to find whether the reaction is exothermic or endothermic.
Formula for change in enthalpy is:-
dH = dU + d(PV)
The above equation can be written in the terms of initial and final states of the system which is defined below:
UF – UI = qP –p(VF – VI)
Or qP = (UF + pVF) – (UI + pVI)
Enthalpy (H) can be written as H= U + PV. Putting the value in the above equation, we obtained:
qP = HF – HI = ∆H
Hence, change in enthalpy ∆H = qP, referred to as the heat consumed at a constant pressure by the system. At constant pressure, we can also write,
∆H = ∆U + p∆V
Standard Enthalpy of Reaction
To specify the standard enthalpy of any reaction, it is calculated when all the components participating in the reaction i.e., the reactants and the products are in their standard form. Therefore the standard enthalpy of reaction is the enthalpy change that occurs in a system when a matter is transformed by a chemical reaction under standard conditions.