The correct stability order of the following diazonium salts is: 
Choose the correct answer from the options given below:
C $>$ A $>$ D $>$ B
Step 1: Basic stability rule for diazonium salts.
Aryl diazonium salts are stabilized by electron donating groups on the benzene ring and destabilized by strong electron withdrawing groups.
Step 2: Effect of substituents.
(A) $-OCH_3$: Strong $+M$ (electron donating) effect, stabilizes diazonium ion greatly.
(C) H: No substituent effect, moderate stability.
(D) $-CN$: Strong $-M$ effect, reduces stability.
(B) $-NO_2$: Very strong $-M$ and $-I$ effects, maximum destabilization.
Step 3: Ordering stability.
\[ \text{A (most stable)}>\text{C}>\text{D}>\text{B (least stable)} \] Step 4: Final conclusion.
The correct stability order is A $>$ C $>$ D $>$ B, corresponding to option (1).
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,