Paper: CSIR-NET June 2016 · Subject: Physical Chemistry · Chapter: Chemical Kinetics · Topic: Rate Laws Order · Marks: 2 · Difficulty: Medium
For the chemical reaction in aqueous solution, $\mathrm{CH}_{2} \mathrm{ClCOO}^{-}+\mathrm{OH}^{-} \rightarrow \mathrm{CH}_{2} \mathrm{OHCOO}^{-}+\mathrm{Cl}^{-}$ the correct statement is
(a)increase of pressure increases the rate constant
(b)increase of dielectric constant increases the rate constant
(c)increase of ionic strength decreases the rate constant
(d)the entropy of activation is positive
Answer
Answer: B ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
Both reactants are anions (like charges): raising the dielectric constant or the ionic strength lowers their electrostatic repulsion and increases k; ΔS‡ is negative because the doubly charged transition state orders the solvent.