What will be the decreasing order of basic strength of the following conjugate bases? OH⁻, RO⁻, CH₃COO⁻, Cl⁻

Step 1: Comparing Basic Strength of Conjugate Bases Basic strength is inversely proportional to the acidic strength of the corresponding conjugate acid.

• $\ce{ROH}$ ($pK_a \sim 16$) $\rightarrow$ Conjugate base: $\ce{RO^-}$
• $\ce{H2O}$ ($pK_a = 15.7$) $\rightarrow$ Conjugate base: $\ce{OH^-}$
• $\ce{CH3COOH}$ ($pK_a = 4.76$) $\rightarrow$ Conjugate base: $\ce{CH3COO^-}$
• $\ce{HCl}$ ($pK_a = -7$) $\rightarrow$ Conjugate base: $\ce{Cl^-}$

Step 2: Conclusion Since acidity order is $\ce{HCl > AcOH > H2O > ROH}$, the basicity order is: $\ce{RO^- > OH^- > CH3COO^- > Cl-}$.

$\boxed{\text{Answer: (b)}}$