If first ionization enthalpies of elements X and Y are 419 kJ mol$$-$$1 and 590 kJ mol$$-$$1, respectively and second ionization enthalpies of X and Y are 3069 kJ mol$$-$$1 and 1145 kJ mol$$-$$1, respectively. Then correct statement is :
The incorrect statement about denaturation of proteins is :
Four gas cylinders containing He, N2, CO2 and NH3 gases separately are gradually cooled from a temperature of 500 K. Which gas will liquify first?
(Given Tc in K $$-$$ He : 5.3, N2 : 126, CO2 : 304.1 and NH3 : 405.5)
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : The metal carbon bond in metal carbonyls possesses both $$\sigma$$ and $$\pi$$ character.
Reason (R) : The ligand to metal bond is a $$\pi$$ bond and metal to ligand bond is a $$\sigma$$ bond.
In the light of the above statements, choose the most appropriate answer from the options given below.