When acetaldehyde is heated with Fehling's solution,it gives a red precipitate of:

What is the product formed when a $Grignard$ reagent $(RMgX)$ reacts with acetone $(CH_3COCH_3)$?

The final product $(C)$ in the given reaction sequence is
$C_6H_5COOH$ $\xrightarrow{SOCl_2} (A)$ $\xrightarrow[\text{anhy. } AlCl_3]{C_6H_6} (B)$ $\xrightarrow[\text{(ii) } KOH / (CH_2OH)_2]{\text{(i) } NH_2-NH_2} (C)$

The reaction sequence is as follows:
$Cyclopentanecarboxamide$ $\xrightarrow{P_2O_5, \Delta} W$ $\xrightarrow{CH_3MgBr, H_3^+O} X$ $\xrightarrow{Ca(OH)_2, I_2 (\text{yellow ppt.})} Y$ $\xrightarrow{\Delta} Z$
$Z$ is:

Arrange the following compounds in order of decreasing reactivity for nucleophilic addition reaction:
$(I)$ $CH_3COCH_2Cl$
$(II)$ $ClCH_2CHO$
$(III)$ $HCHO$
$(IV)$ $CH_3COCH_3$

The major product of the above reaction is $A$.