The reaction shown below is called:
$CH_3-CHO + 4[H] \xrightarrow{Zn-Hg / \text{conc. } HCl} CH_3-CH_3 + H_2O$

Acetone on addition to methyl magnesium bromide forms a complex,which on decomposition with acid gives $X$ and $Mg(OH)Br$. Which one of the following is $X$?

Write the structural formulas and names of the four possible aldol condensation products from propanal and butanal. In each case,indicate which aldehyde acts as the nucleophile and which acts as the electrophile.

Identify the reagent $R$ used in the following reaction:
$\text{Ketone} \xrightarrow{R} \text{Semicarbazone}$

The major product $(Q)$ of the following reaction is:

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