Calculate the value of $x + \text{molecular mass of } (C)$,where $x$ is the number of moles of $PhMgBr$ consumed in reaction $(a)$ and $(C)$ is the gas evolved in reaction $(b)$.
$(a)$ $3\text{-hydroxy-5-formylbenzoyl chloride} + x \ PhMgBr \xrightarrow{\text{excess}} (A)$
$(b)$ $2,5\text{-dioxocyclohexanecarboxylic acid} \xrightarrow{\Delta} (B) + (C) \uparrow$

Find the missing information from the following reactions:
$(i)$ $CH_3COOH \rightarrow[\Delta]{H_2SO_4/P_2O_5} ?$
$(ii)$ $? + CH_3OH \rightleftharpoons[H^{+}]{} CH_3COOCH_3 + H_2O$
$(iii)$ $3 CH_3COOH + PCl_3 \rightarrow 3 CH_3COCl + ?$
$(iv)$ $CH_3COOH + PCl_5 \rightarrow CH_3COCl + ? + HCl$
$(v)$ $C_6H_5COONa \rightarrow{?} C_6H_6$
$(vi)$ $CH_3CH_2COOH \rightarrow{\text{excess } Br_2 + \text{Red } P} ? + ?$
$(vii)$ $CH_3CH_2COOH \rightarrow{?} CH_3CH_2CH_2OH$
$(viii)$ $C_6H_5COOH \rightarrow{\text{anhydrous } AlCl_3, CH_3Cl \text{ or } CH_3COCl} ?$

What combination of acid chloride or anhydride and arene would you choose to prepare the given compound?

The major product of the following reaction sequence is

The major product in the following reaction is

An organic compound $(A)$ (molecular formula $C_{8}H_{16}O_{2}$) was hydrolysed with dilute sulphuric acid to give a carboxylic acid $(B)$ and an alcohol $(C)$. Oxidation of $(C)$ with chromic acid produced $(B)$. $(C)$ on dehydration gives but$-1-$ene. Write equations for the reactions involved.