List - IMolecule | List - IIBond enthalpy (kJ mol-1) |
---|---|
(A) HCl | (I) 435.8 |
(B) N2 | (II) 498 |
(C) H2 | (III) 946.0 |
(D) O2 | (IV) 431.0 |
Bond enthalpy is the energy required to break one mole of a particular bond in a gaseous substance.
A. HCl: The H-Cl bond enthalpy is approximately 431 kJ mol$^{-1}$ (slightly lower than HBr and higher than HF due to periodic trends down the halogen group). Thus, A-IV.
B. N$_2$: The N≡N triple bond is very strong, with a bond enthalpy of approximately 946 kJ mol$^{-1}$. Thus, B-III.
C. H$_2$: The H-H single bond has a bond enthalpy of approximately 436 kJ mol$^{-1}$. Thus, C-I.
D. O$_2$: The O=O double bond has a bond enthalpy of approximately 498 kJ mol$^{-1}$. Thus, D-II.
Therefore, the correct matching is A-IV, B-III, C-I, D-II.
What is the empirical formula of a compound containing 40% sulfur and 60% oxygen by mass?
Given below are two statements :
Statement I : Wet cotton clothes made of cellulose based carbohydrate takes comparatively longer time to get dried than wet nylon polymer based clothes.
Statement II : Intermolecular hydrogen bonding with water molecule is more in nylon-based clothes than in the case of cotton clothes.
In the light of the above statements, choose the Correct answer from the options given below
Match the LIST-I with LIST-II
LIST-I | LIST-II |
---|---|
A. PF5 | I. dsp2 |
B. SF6 | II. sp3d |
C. Ni(CO)4 | III. sp3d2 |
D. [PtCl4]2- | IV. sp3 |
Choose the correct answer from the options given below:
List I | List II | ||
---|---|---|---|
A | Mesozoic Era | I | Lower invertebrates |
B | Proterozoic Era | II | Fish & Amphibia |
C | Cenozoic Era | III | Birds & Reptiles |
D | Paleozoic Era | IV | Mammals |