NEET2018ChemistryRedox ReactionsActual
When CH ₃ COOCH ₃+ HCl is titrated with NaOH then at neutral point the colour of phenolphthalein becomes colourless from pink due to
Options
- Aformation of CH ₃ OH
- Bformation of CH ₃ COOH which acts as a weak acid
- Cphenolphthalein vaporizes
- Dpresence of HCl .
Correct answer
B. formation of CH ₃ COOH which acts as a weak acid
Step-by-step solution
NaOH solution is taken in a conical flask with phenolphthalein indicator (pink colour) and CH ₃ COOCH ₃+ HCl solution is added from burette slowly. First, HCl left after hydrolysis of ester (being a strong acid) gets consumed then CH ₃ COOH being a weak acid will bring the titration to the neutralisation point. aligned & CH ₃ COOCH ₃ H ₂ O H ⁺ CH ₃ COOH + CH ₃ OH & HCl + NaOH NaCl + H ₂ O & CH ₃ COOH + NaOH CH ₃ COONa aligned