question_answer

The reagent with which both acetaldehyde and acetone react easily is

A)  Schiff s reagent

B)  Tollens reagent

C)  Grignard reagent

D)  Fehling solution

Correct Answer: C

Solution :

                 Acetaldehyde and acetone react with Grignard reagent. Acetaldehyde gives the secondary alcohol with Grignard reagent while acetone gives tertiary alcohol with Grignard reagent. \[C{{H}_{3}}CHO+RMgX\xrightarrow{{}}C{{H}_{3}}-\overset{\begin{smallmatrix}  H \\  | \end{smallmatrix}}{\mathop{\underset{\begin{smallmatrix}  | \\  R \end{smallmatrix}}{\mathop{C}}\,}}\,-OMgX\]                 But with Schiffs reagent, Tollens reagent, and Fehlings solution only acetaldehyde reacts. (Acetone does not react with these reagents \[RCHO\text{ }+\underset{\left( colourless \right)}{\mathop{Schiffs\text{ }reagent}}\,\xrightarrow{{}}\] pink colour \[R-CHO+\underset{Tollens\text{ }reagent}{\mathop{A{{g}_{2}}O}}\,\xrightarrow{\Delta }\,R.COOH\] \[\underset{silver\text{ }mirror}{\mathop{+2Ag}}\,\] \[R-CHO+\underset{\begin{smallmatrix}  blue \\  Fehlings\text{ }solution \end{smallmatrix}}{\mathop{2CuO}}\,\xrightarrow{\Delta }R\,.\,COOH\] \[\underset{red\text{ }ppt.}{\mathop{+C{{u}_{2}}O}}\,\]