The major product formed in the following reaction sequence is $CH_3-CH=CH_2$ $\xrightarrow[\substack{(iii) \ CH_3-CH_2-CHO \\ (iv) \ CrO_3}]{\substack{(i) \ HBr, \text{ peroxide} \\ (ii) \ Mg}}$

Complete each synthesis by providing the missing starting material, reagent, or products for the following reactions:

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$ : $Image-I$ can be easily reduced using $Zn-Hg / HCl$ to $Image-II$.
Reason $R : Zn-Hg / HCl$ is used to reduce carbonyl group to $-CH_2-$ group.
In the light of the above statements,choose the correct answer from the options given below:

Compound $CH_3-CO-CH_2-OH$ reduces:

What is $X$ in the following reaction?
$2 CH_3COCH_3 \stackrel{Ba(OH)_2}{\longrightarrow} X$

The correct order of reactivity for the addition reaction of the following carbonyl compounds with ethylmagnesium iodide is: