In Wolff-Kishner reduction,the carbonyl group of aldehydes and ketones is converted into

Identify the correct statement regarding the following sequence of reactions:
$3\text{-methylbut-1-ene}$ $\xrightarrow[(ii) NaBH_4]{(i) Hg(OCOCH_3)_2/H_2O} A$ $\xrightarrow{\Delta, H_2SO_4} B (\text{major alkene})$ $\xrightarrow{O_3/Zn} C + D$

Which of the following methods can be used to oxidize $Butan-2-one$ to $Propionic \ acid$?

Ethylene is converted to $X$ on passing through a mixture of an acidified aqueous solution of palladium chloride and cupric chloride. Which of the following reagents readily take part in addition reaction with $X$?

In the reaction scheme shown below,$Q$,$R$,and $S$ are the major products. Identify the correct structure of the products from the given options:
$(P)$ + Succinic anhydride $\xrightarrow{AlCl_3}$ $Q$
$Q$ $\xrightarrow[H_3PO_4]{Zn-Hg/HCl}$ $R$
$R$ $\xrightarrow[(ii) H_3O^+]{(i) CH_3MgBr, (iii) H_2SO_4/\Delta}$ $S$
$(A)$ $S$ is [Structure $A$]
$(B)$ $Q$ is [Structure $B$]
$(C)$ $R$ is [Structure $C$]
$(D)$ $S$ is [Structure $D$]

When liquid $A$ is treated with a freshly prepared ammoniacal silver nitrate solution,it gives a bright silver mirror. The liquid forms a white crystalline solid on treatment with sodium hydrogensulphite. Liquid $B$ also forms a white crystalline solid with sodium hydrogensulphite but it does not give a test with ammoniacal silver nitrate. Which of the two liquids is an aldehyde? Write the chemical equations of these reactions also.