Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Melting point of Boron ( 2453 K) is unusually high in group 13 elements.
Reason (R) : Solid Boron has very strong crystalline lattice.
In the light of the above statements, choose the most appropriate answer from the options given below ;
Assertion (A) : Melting point of Boron ( 2453 K) is unusually high in group 13 elements.
Reason (R) : Solid Boron has very strong crystalline lattice.
In the light of the above statements, choose the most appropriate answer from the options given below ;
- (A)Both (A) and (R) are correct but (R) Is not the correct explanation of (A)
- (B)Both (A) and (R) are correct and (R) is the correct explanation of (A)✓ Correct
- (C)(A) is true but (R) is false
- (D)(A) is false but (R) is true
Answer: (B)
Solution
Assertion: boron's melting point (2453 K) is indeed unusually high among group 13 elements — true.
Reason: solid boron forms an exceptionally strong, three-dimensional covalent crystalline lattice built from icosahedral units — true, and this strong lattice is exactly why so much thermal energy is needed to melt it. The reason correctly explains the assertion.
Reason: solid boron forms an exceptionally strong, three-dimensional covalent crystalline lattice built from icosahedral units — true, and this strong lattice is exactly why so much thermal energy is needed to melt it. The reason correctly explains the assertion.
JEE Main · 2024 · 27 Jan 2024 · Shift 1 · Single correct option