Write the correct order of rate of reaction of following with PhN$_2$Cl 
The rate of reaction with PhN$_2$Cl (azo coupling) is affected by substituents on the aromatic ring. Electron-donating groups (EDGs) increase the electron density of the ring, making it more nucleophilic and increasing the rate.
1. R has an NH$_2$ group, which is a strong EDG (+M effect).
2. P has a CH$_3$ group, which is a weak EDG (+I and hyperconjugation).
3. Q has an NO$_2$ group, which is a strong electron-withdrawing group (-M effect).
Thus, the correct order of reaction rate is R>P>Q.
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,