Which of the following acids cannot be prepared by a Grignard reagent?

What is obtained when glycerol is heated with oxalic acid at $110\,^{\circ}C$?

$A \xrightarrow[\begin{smallmatrix} (ii) CN^{-} \\ (iii) H_{2}O/H^{+} \end{smallmatrix}]{(1) Cl_{2}, \Delta }$ $4-$Bromophenyl acetic acid.
In the above reaction '$A$' is ....

What is the name of the given reaction? $CH_3CH = CH_2 \xrightarrow[(CO + H_2)]{H^+} CH_3 - CH(COOH) - CH_3$

Consider the following reactions. From these reactions,which reaction will give carboxylic acid as a major product?
$(A)$ $R-C \equiv N \xrightarrow[(i) H^{+}/H_2O]{\text{mild condition}} R-CONH_2$
$(B)$ $R-MgX \xrightarrow[(ii) H_3O^{+}]{\text{(i) } CO_2} R-COOH$
$(C)$ $R-C \equiv N \xrightarrow[(ii) H_3O^{+}]{\text{(i) } SnCl_2/HCl} R-CHO$
$(D)$ $R-CH_2-OH \xrightarrow{PCC} R-CHO$
$(E)$ $\text{Benzoyl chloride} \xrightarrow[(ii) Br_2/H_2O]{\text{(i) } H_2/Pd-BaSO_4} \text{Benzoic acid}$
Choose the correct answer from the options given below:

Which of the following on hydrolysis forms acetic acid?