Solvent effects on reactions

27 questions on Solvent effects on reactions from the Organic Reaction Mechanisms I: Nucleophiles and Carbonyl Addition chapter: 5 NEET level, 11 JEE Main, 11 JEE Advanced. Each one opens with its answer and solution.

• Which of the following is a polar protic solvent? NEET level
• For the S_N2 reaction of CH3Br with NaN3 at the same concentrations, the rate is highest in NEET level
• The S_N1 solvolysis of (CH3)3C-Cl is fastest in NEET level
• In water, F- is a poorer nucleophile than I- mainly because NEET level
• In methanol (a polar protic solvent), the correct order of nucleophilicity of the halide ions is NEET level
• The rate of the S_N2 reaction CH3I + N3- -> CH3N3 + I- is far greater in DMF than in methanol. The best explanation is that JEE Main level
• The S_N1 solvolysis of (CH3)3C-Cl is carried out in pure ethanol and then in 50% aqueous ethanol. The rate in the aqueous mixture is JEE Main level
• For the reaction HO- + CH3Br -> CH3OH + Br- carried out in ethanol-water mixtures, increasing the proportion of water produces JEE Main level
• Which of the following statements are correct? JEE Main level
• Which of the following are polar aprotic solvents? JEE Main level
• In DMSO the nucleophilicity of the halide ions toward CH3I follows the order JEE Main level
• In methanol, toward CH3I, CH3S- is a better nucleophile than CH3O- although CH3SH is more acidic than CH3OH. The reason is that JEE Main level
• Potassium fluoride is nearly unreactive toward 1-bromobutane in acetonitrile, but reacts rapidly after adding 18-crown-6. This is because the crown ether JEE Main level
• Methylmagnesium bromide cannot be used in ethanol as solvent because JEE Main level
• In the Finkelstein reaction R-Cl + NaI -> R-I + NaCl, acetone is the preferred solvent because JEE Main level
• Taking a protic solvent to be one with hydrogen attached to oxygen or nitrogen, which of the following is a polar protic solvent? JEE Main level
• Toward CH3I in methanol, in which of the following pairs is the first species the stronger nucleophile? JEE Advanced level
• Relative rate constants (hypothetical, all scaled to Cl- in methanol = 1.0) for CH3I + X- -> CH3X + I- at 25 degC are: in methanol, Cl- 1.0, Br- 20, I- 90; in D... JEE Advanced level
• When the solvent is changed from ethanol to a more polar ethanol-water mixture, the rates of (P) (C2H5)3N + CH3I -> (C2H5)3N+-CH3 I-, (Q) the S_N1 solvolysis of... JEE Advanced level
• Cyclohexanone is to be treated with CH3MgBr in a suitable solvent, followed by aqueous work-up. Which solvents are suitable for the addition step? JEE Advanced level
• Cyclohexanone is converted into its ethylene glycol acetal using ethylene glycol and a catalytic amount of TsOH in refluxing benzene. Which modification would b... JEE Advanced level
• The S_N1 solvolysis of (CH3)3C-Br is followed in aqueous acetone. Which statements are correct? JEE Advanced level
• The pKa of acetic acid is 4.76 in water but 12.3 in DMSO. This large difference arises because JEE Advanced level
• Which combination would give the fastest conversion of 1-bromobutane into 1-fluorobutane using potassium fluoride? JEE Advanced level
• Which of the following reactions proceed predominantly by the S_N2 pathway? JEE Advanced level
• When (CH3)3C-Br is dissolved in 50% aqueous ethanol it gives both (CH3)3C-OH and (CH3)3C-O-C2H5. The most direct inference is that JEE Advanced level
• Solvents are: water, DMSO, hexane, methanol. Which pair correctly names the solvent giving the fastest S_N1 solvolysis of (CH3)3C-Cl and the solvent giving the ... JEE Advanced level