Solution:
Statement I: Boron is extremely hard indicating its high lattice energy.
Boron forms a giant covalent structure rather than an ionic lattice. Its hardness is due to its strong covalent network, not high lattice energy. Therefore, Statement I is incorrect.
Statement II: Boron has the highest melting and boiling point compared to its other group members.
Boron has a very high melting and boiling point due to its strong covalent network structure. This is true compared to the other group 13 elements. Therefore, Statement II is correct.
Therefore, Statement I is incorrect but Statement II is correct.
Correct Answer: (1) Statement I is incorrect but Statement II is correct
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,